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Prof. Sachrajda25/07/2016, 09:00
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Urs Wenger (University of Bern)25/07/2016, 09:15From Spin Models to Lattice QCD – the Scientific Legacy of Peter HasenfratzGo to contribution page
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Prof. Chuan Liu (Peking University)25/07/2016, 09:45I review the recent lattice results on spectroscopy and resonances in the past years. For the conventional hadron spectrum computations, focus has been put on the isospin breaking effects, QED effects, and simulations near the physical point. I then go through several single-channel scattering studies using Luescher formalism which has matured over the past years. The topics cover light...Go to contribution page
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Dr David Wilson (University of Cambridge)25/07/2016, 10:30Excited states in hadron physics are seen as resonances in the scattering of lighter stable hadrons like $\pi$, $K$ and $\eta$. Many decay into multiple final states necessitating coupled-channel analyses. Recently it has become possible to obtain coupled-channel scattering amplitudes from lattice QCD. Using large diverse bases of operators it is possible to obtain reliable finite volume...Go to contribution page
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Prof. Hartmut Wittig (University of Mainz)25/07/2016, 11:30The overall accuracy of the Standard Model prediction of the anomalous magnetic moment of the muon is currently limited by hadronic effects. I review the status of lattice QCD calculations, aimed at providing precise estimates for the hadronic vacuum polarisation and hadronic light-by-light scattering contributions, respectively. In the case of the leading hadronic vacuum polarisation...Go to contribution page
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Sergei Dubovsky (NYU)25/07/2016, 12:15I will review recent advances in describing the dynamics of the QCD string (confining flux tube) both on theoretical and on lattice sides. I will argue that combined efforts of theorists and lattice practitioners may result in a dramatic progress in our understanding of the world sheet theory of the QCD string in the nearest future.Go to contribution page
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Dr Stephan Durr (University of Wuppertal)25/07/2016, 14:15First experiences are reported with overlap fermions which employ the Brillouin action as a kernel. After discussing the dispersion relations of both the kernel and the resulting chiral action, some of the physics features are addressed on quenched backgrounds. We find that the overlap with Brillouin kernel is much better localized than the overlap with Wilson kernel. Also a preliminary...Go to contribution page
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Dr Renwick J. Hudspith (York University)25/07/2016, 14:15We present results of the hadron spectrum using $n_f=2+1$ ensembles with pion masses as low as 156(4) MeV, we place particular emphasis on measurements of the singly and doubly heavy charm and bottom baryons. Using the Tsukuba tuning for relativistic charm and NRQCD for the bottom quarks we perform measurements of both light and heavy mesons as well as spin-1/2 and spin-3/2 baryons for all...Go to contribution page
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Dr Christian Wiese (NIC - DESY Zeuthen)25/07/2016, 14:15Although parton distribution functions are the fundamental objects describing the inner structure of hadrons, they were so far not calculated from first principles. In the past, lattice QCD has successfully been employed for the computation of hadronic spectra and form factors. Yet calculations of quark distributions are still missing, since they are given by light-cone correlation functions...Go to contribution page
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Dr vincent Drach (CERN)25/07/2016, 14:15We present a non perturbative study of SU(2) gauge theory with two fundamental Dirac flavours. This theory provides a minimal template which is ideal for a wide class of Standard Model extensions featuring novel strong dynamics. After reviewing our findings for the Goldstone bosons and spin-1 spectrum, we present our new results for the sigma and eta states. We evaluate the relevant...Go to contribution page
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Dr Wolfgang Bietenholz (UNAM, Mexico)25/07/2016, 14:15In simulations of a model with topological sectors, algorithms which proceed in small update steps tend to get stuck in one sector, especially on fine lattices. This distorts the numerical results; in particular it is not straightforward to measure the topological susceptibility chi_t. Here we test a method to measure chi_t even if configurations from only one sector are available....Go to contribution page
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Kalman Szabo (U Wuppertal, FZ Juelich)25/07/2016, 14:15Finite temperature lattice QCD is investigated with four flavor physical mass staggered quarks using lattices upto N_t=20. Results for the equation of state and the low-lying modes of the Dirac-operator are presented with a focus on lattice artefacts.Go to contribution page
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Dr Julien Frison (KEK Theory Center)25/07/2016, 14:35On the lattice, many definitions of the topological charge $Q$ coexist, and can give very different numbers on a given configuration. Those definitions will only converge when one takes the continuum limit of the moments $\langle Q^n\rangle$ (provided that $Q$ has been correctly renormalised). Additionally, other complications arise when one wants to study the mass dependence of the...Go to contribution page
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Dr Anthony Francis (York University)25/07/2016, 14:35Having introduced the ensembles and basic spectrum in Part I, we focus on results for a doubly heavy tetraquark candidate, $qq\bar Q \bar Q$. Based on phenomenological observations regarding heavy baryon systems, we motivate two possible lattice interpolating operators: a diquark-anti diquark and a meson-meson. We show these operators exhibit good behaviour both in terms of lattice QCD and...Go to contribution page
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Prof. Anna Hasenfratz (University of Colorado)25/07/2016, 14:35We construct a prototype BSM model where the Higgs boson is a pseudo Nambu-Goldstone boson by combining 4 light (massless) flavors and 8 heavy flavors. In the infrared, the SU(4) chiral symmetry is spontaneously broken , while in the ultraviolet it exhibits the properties of the $N_f=12$ conformal fixed point. The running coupling of this system ``walks" and the energy range of walking can...Go to contribution page
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Dr YIBO Yang (university of Kentucky)25/07/2016, 14:35I shall report on the progress of the proton spin decomposition based on Ji’s scheme and also the necessary perturbative calculation, to convert them from the lattice regularization to MS-bar scheme at 2 GeV.Go to contribution page
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Dr Johannes Heinrich Weber (Technische Universität München)25/07/2016, 14:35I discuss QCD with Flavored Minimally Doubled Fermions as sea quarks. Minimally Doubled Fermions are an ultra-local formulation that realizes a non-singlet chiral symmetry with only two real fermions at finite lattice cutoff, but break the hypercubic symmetry as well as some discrete space-time symmetries. I show that the broken discrete space-time symmetries do not affect vacuum since the...Go to contribution page
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Prof. Sandor Katz Katz (Eotvos University, Budapest)25/07/2016, 14:35We study the QCD transition with dynamical overlap fermions. A continuum extrapolation is carried out using lattices up to N_t=12. We use a fixed topology approach and study its effect on our observables.Go to contribution page
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Zhaofeng LIU (Institute of High Energy Physics, Chinese Academy of Sciences, Beijing)25/07/2016, 14:55Using 2+1-flavor domain wall fermion configurations, we calculate the overlap quark propagator in the Landau gauge. Then we try to extract the chiral condensate from the operator product expansion of the quark propagator in momentum space.Go to contribution page
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Prof. Shailesh Chandrasekharan (Duke University)25/07/2016, 14:55In this talk we argue that the fermion bag formulation extends the concepts of topology and index theorems associated with non-Abelian gauge theories, to simple lattice fermion field theories. Through such a connection we learn that fermion masses can arise in at least two different ways:(1) a conventional way where some lattice symmetry of the action is spontaneously, explicitly or...Go to contribution page
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Mr Gavin Cheung (University of Cambridge)25/07/2016, 14:55We present searches for tetraquarks in lattice QCD with quark content $cc\bar{q}\bar{q}$ and isospin-1 $c\bar{c}q\bar{q}$ which are especially of relevance to the experimentally observed charged $Z_c$ states. Utilising the variational method, we employ a large bases of operators consisting of diquark-antidiquark and meson-meson operators. We show the spectra determined across a range of...Go to contribution page
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Michael Engelhardt (New Mexico State University)25/07/2016, 14:55Quark orbital angular momentum (OAM) in the nucleon can be evaluated directly by employing a Wigner function embodying the simultaneous distribution of parton transverse position and momentum. This distribution can be accessed via a generalization of the nucleon matrix elements of quark bilocal operators which have been used previously in the lattice evaluation of transverse...Go to contribution page
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Prof. Claudio Rebbi (Boston University)25/07/2016, 14:55We present our results for the spectrum and other observables of an SU(3) gauge theory with 4 light fermions and 8 fermions of heavier mass, built on an IR fixed point. Our numerical data validate hyperscaling and, while our model does not presume to be a complete theory of EW symmetry breaking, it exhibits many of the features that would be expected of a realistic theory where the...Go to contribution page
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Dr Szabolcs Borsanyi (University of Wuppertal)25/07/2016, 14:55We give a lattice-based description of QCD thermodynamics in the hadronic phase from staggered simulations of up to $N_t=16$. Using generalized quark number susceptibilities we obtain the free energy in various strangeness sectors and compare it with the expectations from the hadron resonance gas model. We use the findings to disambiguate between various spectrum tables. Thus we...Go to contribution page
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Dr Philippe de Forcrand (ETH Zurich & CERN)25/07/2016, 15:15In its lower left corner, the Columbia plot indicates a first-order finite-temperature phase transition, which turns into a crossover as the quark masses increase. The locus of quark masses giving a second-order transition is a feature of continuum QCD, and should be recovered with any fermion discretization. However, numerical evidence has been accumulating, disfavoring universality. We...Go to contribution page
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Dr Shoji Hashimoto (KEK)25/07/2016, 15:15We calculate the spectral function of the Mobius domain-wall Dirac operator utilizing a stochastic eigenvalue counting technique. From the low-end of the spectrum we extract the chiral condensate in 2+1-flavor QCD, and take the chiral and continuum limits. Lattice ensembles are those generated with Mobius domain-wall fermions at a~0.080, 0.055 and 0.044 fm.Go to contribution page
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Prof. Pedro Bicudo (Universidade de Lisboa)25/07/2016, 15:15In previous works we predicted the existence of a $\bar{b} \bar{b} u d$ tetraquark with quantum numbers $I(J^P) = 0(1^+)$ using the static approximation for the $\bar{b}$ quarks and neglecting heavy spin effects. Since the binding energy is of the same order as expected for these heavy spin effects, it is essential to include them in the computation. Here we present a corresponding method and...Go to contribution page
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Dr Simon Mages (Forschungszentrum Jülich)25/07/2016, 15:15A common problem in lattice QCD simulations on the torus is the extremely long autocorrelation time of the topological charge, when one approaches the continuum limit. The reason is the suppressed tunneling between topological sectors. The problem can be addressed by replacing the torus with a different manifold. Here we propose to use a non-orientable manifold, and show how to define and...Go to contribution page
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Prof. Julius Kuti (U.C. San Diego)25/07/2016, 15:15Based on recent analysis of the LatHC collaboration I will review critical features of a minimal composite Higgs model close to the conformal window. Challenging problems of the near-conformal paradigm will be compared with PNGB based partial compositeness.Go to contribution page
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Prof. Constantia Alexandrou (University of Cyprus and The Cyprus Institute)25/07/2016, 15:15The quark contributions to the spin and mass of the nucleon are computed using $N_f=2$ twisted mass fermions with a physical value of the pion mass. We use improved methods to obtain accurate results for the disconnected contributions involved in the evaluation of the axial charge and quark momentum fraction as well as the light, the strange and the charm $\sigma$-terms.Go to contribution page
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Dr Yoshifumi Nakamura (RIKEN)25/07/2016, 15:35We investigate the critical endline of the finite temperature phase transition of QCD around the SU(3)-flavor symmetric point at zero chemical potential. We employ the renormalization-group improved Iwasaki gauge action and non-perturbatively $O(a)$-improved Wilson-clover fermion action. The critical endline is determined by using the intersection point of kurtosis, employing the...Go to contribution page
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Dr Balint Toth (Bergische Universität Wuppertal)25/07/2016, 15:35A common problem in lattice QCD simulations on the torus is the extremely long autocorrelation time of the topological charge, when one approaches the continuum limit. The reason is the suppressed tunneling between topological sectors. The problem can be addressed by replacing the torus with a different manifold. Here we propose to use a non-orientable manifold, and show how to define and...Go to contribution page
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Ms Antje Peters (Goethe-Universität Frankfurt am Main)25/07/2016, 15:35We study $\bar{b} \bar{b} u d$ and $\bar{b} b u \bar{d}$ four-quark systems using lattice QCD. The heavy b quarks are treated either in the static approximation or by using NRQCD. Both for $\bar{b} \bar{b} u d$ (quantum numbers $I(J^P) = 0(1^+)$) and for $\bar{b} b u \bar{d}$ (quantum numbers of $Z_b$, $I(J^P) = 1(1^+)$) our results indicate the existence of a four-quark bound state, i.e. a tetraquark.Go to contribution page
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Dr Georg Bergner (AEC ITP University of Bern)25/07/2016, 15:35In this work I will summarize our results concerning the spectrum and mass anomalous dimension of SU(2) gauge theories with a different number of fermions in the adjoint representation, where each Majorana fermion corresponds effectively to half a Dirac flavour $N_f$. The most relevant examples for the extensions of the standard model are supersymmetric Yang-Mills theory ($N_f=1/2$) and...Go to contribution page
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Dr Christian Hoelbling (Wuppertal University)25/07/2016, 15:35We construct domain wall fermion operators with a staggered kernel and investigate their spectral and chiral properties numerically in the Schwinger model. In some relevant cases we see an improvement of chirality by more than an order of magnitude compared to standard domain wall fermions.Go to contribution page
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Dr James Zanotti (University of Adelaide)25/07/2016, 15:35Fourier transforms of electromagnetic form factors provide valuable insights into the spatial distribution of quarks/charge within a hadron. When combined with form factors arising from non-forward matrix elements of the tensor operator, we are able to unlock fascinating information into the distribution of transversely polarised/unpolarised quarks within a transversely polarised/unpolarised...Go to contribution page
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Sergey Syritsyn (Jefferson Lab)25/07/2016, 15:55In typical nucleon structure calculations on a lattice, the interpolating fields are optimized to overlap with the nucleon ground state at rest, which in practice limits the momentum transfer in form factors to $Q^2\le 1\,GeV^2$. There is great interest in studying nucleon form factors up to few tens of GeV^2. New experiments at the JLab 12-GeV upgrade will measure nucleon form factors with...Go to contribution page
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Dr Ed Bennett (Swansea University)25/07/2016, 15:55Motivated by tentative signals of new physics at the LHC, which seems to imply the presence of large mass hierarchies, we investigate the theoretical possibility that these could arise dynamically in new strongly-coupled gauge theories extending the standard model of particle physics. To this purpose, we study lattice data on non-Abelian gauge theories in the (near-)conformal...Go to contribution page
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Arata Yamamoto (University of Tokyo)25/07/2016, 15:55The Berry curvature is a fundamental concept describing topological order of quantum systems. While it can be analytically tractable in non-interacting systems, numerical simulations are necessary in interacting systems. We present a formulation to calculate the Berry curvature in lattice QCD.Go to contribution page
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Edwin Laermann (Bielefeld University)25/07/2016, 15:55We present recent results for QCD at non-vanishing chemical potentials for baryon number, electric charge and strangeness. The results are obtained from Taylor expanding the QCD partition function up to sixth order in these potentials. The numerical simulations for two light and one strange quark have been carried out on the basis of the Highly Improved Staggered Quark (HISQ) discretization...Go to contribution page
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Mr Ryutaro Fukuda (University of Tokyo, RIKEN BNL Research Center)25/07/2016, 15:55In recent years, exotic hadrons called X, Y, Z which cannot be explained by the quark model have been found one after another. For example, the tetraquark state, which is one of the typical scenarios to interpret the exotic state, is based on the existence of a diquark state. The discovery of a pentaquark state at CERN in July last year also makes a diquark state even more important. It is...Go to contribution page
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Jacek Wosiek (Jagellonian University)25/07/2016, 16:45A positive representation for an arbitrary complex, gaussian weight is derived and used to construct a statistical formulation of gaussian path integrals directly in the Minkowski time. The positivity of Minkowski weights is achieved by doubling the number of real variables. The continuum limit of the new representation exists only if some of the additional couplings tend to infinity and...Go to contribution page
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Andre Walker-Loud (LBNL)25/07/2016, 16:45Motivated by the Feynman-Hellman Theorem, we develop an improved method for computing matrix elements of external currents utilizing only two-point correlation functions. The contamination from excited states is shown to be Euclidean-time dependent allowing for a significantly improved ability to reliably determine and control the systematics. We demonstrate the utility of our method with a...Go to contribution page
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Mr Joshua Berlin (University of Frankfurt)25/07/2016, 16:45To investigate the light scalar tetraquark candidate $a_0(980)$ (quantum numbers $J^P=0^+$), a correlation matrix including a variety of two- and four-quark interpolating operators has to be computed. We discuss efficient techniques to compute the elements of this correlation matrix. In particular we present numerical results for diagrams with closed quark loops and present evidence that such...Go to contribution page
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Prof. Stefan Sint (Trinity College Dublin)25/07/2016, 16:45A collaborative effort to determine the $\Lambda$-parameter in 3-flavour QCD by the ALPHA collaboration is currently being finalized. The strategy involves 2 finite volume schemes for the coupling, both defined with Schroedinger functional (SF) boundary conditions. I here discuss the scale evolution from an intermediate scale $1/L_0$ of about 4 GeV to scales of O(100) GeV using the...Go to contribution page
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Dr Tanmoy Bhattacharya (Los Alamos National Laboratory)25/07/2016, 16:45The quark chromo-electric dipole moment operator and the pseudo-scalar fermion bilinear with which it mixes under renormalization can both be included in a calculation of the electromagnetic form factor of the nucleon using the Schwinger source method. A preliminary calculation of these operators using clover quarks on HISQ lattices generated by MILC collaboration will be presented showing...Go to contribution page
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Mr Christopher Czaban (Goethe University Frankfurt am Main)25/07/2016, 16:45QCD at zero baryon density in the limit of infinite quark mass undergoes a first order deconfinement phase transition at a critical temperature T_c corresponding to the breaking of the global centre symmetry. In the presence of dynamical quarks the global centre symmetry is explicitly broken. Lowering the quark mass the first order phase transition weakens and terminates in a second order...Go to contribution page
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Dr Yigal Shamir (Tel Aviv University)25/07/2016, 17:05Recent simulations suggest the existence of a very light singlet scalar in QCD-like theories that may be lying just outside the conformal window. Assuming that the lightness of this scalar can be explained by an approximate dilatation symmetry, we develop an effective field theory framework for both the pions and this light scalar, the "dilatonic meson." We argue that a power counting...Go to contribution page
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Mr Alexander Chambers (University of Adelaide)25/07/2016, 17:05Although hadron structure calculations in lattice QCD have improved greatly in recent years, many problems still remain. Various techniques for determining fermion line disconnected contributions to matrix elements have produced exciting and promising results, but rely on complicated analyses. Additionally, calculations of electromagnetic form factors at high momentum transfers remain...Go to contribution page
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Mr Hikaru Kawauchi (Kanazawa University)25/07/2016, 17:05We investigate the phase structure of the lattice CP(N-1) model in two dimensions by using the tensor renormalization group (TRG) method. The TRG method has no sign problem even though the action is complex. We focus on the case N=2 and compare the numerical result of the TRG method with that of the strong-coupling analysis in the presence of the theta term.Go to contribution page
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Mr Alessandro Sciarra (Goethe Universität)25/07/2016, 17:05The QCD phase diagram at imaginary chemical potential exhibits a rich structure and studying it can constrain the phase diagram at real values of the chemical potential. Moreover, at imaginary chemical potential standard numeric techniques based on importance sampling can be applied, since no sign problem is present. In the last decade, a first understanding of the QCD phase diagram at...Go to contribution page
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Dr Alberto Ramos (CERN)25/07/2016, 17:05A fundamental step in the ALPHA collaboration efforts to determine the fundamental parameters of $N_f=3$ QCD at the electroweak scale in terms of hadronic quantities is the connection of an intermediate scale $\sim 4{\rm GeV}$ with a hadronic scale. In this talk we will show that using the Gradient Flow running coupling this task can be achieved with a very high precision. Our analysis...Go to contribution page
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Dr Jacob Finkenrath (german)25/07/2016, 17:05We present an alternative method to the Generalized Eigenvalue Problem (GEVP) for extracting excited states. The method is based on statistically sampling the space of possible set of parameters according to the $\chi^2$-value of each set of values. This method is particularly suited when one has noisy data as is the case for some correlators at large times such as in the scalar light qqbar...Go to contribution page
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Mr Tobias Neitzel (Goethe University Frankfurt)25/07/2016, 17:25We present a method for computing the static quark-antiquark potential, which is not based on Wilson loops, but where the trial states are formed by eigenvector components of the covariant Laplace operator. We have tested this method in SU(2) Yang-Mills theory and obtained results with statistical errors of similar magnitude compared to a standard Wilson loop computation. The runtime of...Go to contribution page
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Prof. Maarten Golterman (San Francisco State University)25/07/2016, 17:25We consider applications of a recently developed effective field theory for a dilatonic meson and pions. We contrast the leading-order behavior of masses with that in a theory with only pions, comment on next-to-leading order, and argue that the effective theory breaks down at the sill of the conformal window, as it should.Go to contribution page
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Dr Shigemi Ohta (KEK)25/07/2016, 17:25Nucleon isovector vector- and axialvector-current form factors and some low moments of isovector structure functions will be reported with improved statistics from four recent RBC+UKQCD 2+1-flavor dynamical drain-wall fermions ensembles: Iwasaki gauge 24^3x64 at 1.78-GeV momentum cut off and pion mass of 432 ans 330 MeV and Iwasaki times DSDR gauge 32^3x64 at 1.38 GeV momentum cut off and pion...Go to contribution page
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Prof. Rainer Sommer (NIC @ DESY)25/07/2016, 17:25The ALPHA-collaboration computation of the three-flavor Lambda-parameter and the determination of $\alpha(m_Z)$ consists of the steps: Running from beyond the Z-mass to 4 GeV in the SF scheme, matching to the GF scheme, running from 4GeV to small energy in the GF scheme, determining the smallest energy scale ($\approx$ 200 MeV) in physical units with the help of the CLS...Go to contribution page
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Ms Francesca Cuteri (Goethe University - Frankfurt)25/07/2016, 17:25The attempt at clarifying the order of the thermal transition in the chiral limit of QCD at zero chemical potential, with two dynamical flavours of quarks, by progressively decreasing the simulated pion mass has proven to be inconclusive because of the increasing costs of the simulations as the pion mass is lowered. An alternative way to approach this question is to consider the path...Go to contribution page
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Stefan Kühn (Max Planck Institute of Quantum Optics)25/07/2016, 17:25During recent years there has been quite some interest in applying Matrix Product States and more general tensor networks to lattice gauge theories in the Hamiltonian formulation. Previous work already demonstrated the power of this approach by computing the mass spectrum and thermal sates for the Schwinger model, and also real-time dynamics for abelian and non-abelian gauge models have been...Go to contribution page
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Ms Tugba Buyukbese (University of Sussex)25/07/2016, 17:45Recently, new four-dimensional (gauge-Yukawa) theories have been discovered which display exact interacting fixed points at highest energies. In a regime where asymptotic freedom is lost, these novel types of theories develop an asymptotically safe UV fixed point, strictly controlled by perturbation theory. In this talk, we extend these studies to include couplings with non-vanishing...Go to contribution page
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Dr Eliana Lambrou (University of Wuppertal)25/07/2016, 17:45We present preliminary results to determine the strong coupling constant by using the gradient flow. Pure SU(3) gauge theory is studied. We carry out a direct analysis on very fine zero temperature lattices. In addition we attempt to move towards the perturbative regime by using step-scaling.Go to contribution page
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Dr Pavel Buividovich (Regensburg University)25/07/2016, 17:45I present a Diagrammatic Monte-Carlo algorithm for the large N SU(N)xSU(N) principal chiral model, which stochastically samples planar Feynman diagrams of the lattice perturbation theory. The latter is constructed using the Cayley map from SU(N) group manifold to the space of Hermitian matrices. I demonstrate that the Jacobian of this map results in the massive bare lattice propagator with the...Go to contribution page
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Prof. Keh-Fei Liu (University of Kentucky)25/07/2016, 17:45I shall report on calculations of isovector matrix elements of the nucleon, such as $g_A, g_s$, and $\langle x \rangle$ on the $48^3 \times 96$ lattice with pion mass at 139 MeV and lattice size of 5.5 fm. We employ overlap valence fermion on the 2+1 flavor DWF configurations for the calculation. Also reported will be the strange quark momentum fraction and its magnetic moment from this...Go to contribution page
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Dr Kouji Kashiwa (Yukawa Institute for Theoretical Physics, Kyoto University)25/07/2016, 17:45We propose a new determination of the confinement-deconfinement transition by using the imaginary chemical potential. The imaginary chemical potential can be interpreted as the Aharonov-Bohm phase and then an analogy of the topological-order suggests that the Roberge-Weiss endpoint would define the deconfinement temperature. Based on the topological property, we can construct a new quantity...Go to contribution page
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Prof. Francesco Knechtli (University of Wuppertal)25/07/2016, 17:45Recently the LHCb experiment found evidence for the existence of two exotic resonances consisting of $c\bar{c}uud$ quarks. Among the possible interpretations there is the hadro-charmonium model, in which charmonium is bound "within" a hadron. We test this idea on CLS $n_f$=2+1 lattices using the static formulation for the heavy quarks. We find that the static potential is modified by the...Go to contribution page
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Mr Ciaran Hughes (University of Cambridge)25/07/2016, 18:05Throughout the literature, phenomenological models have been unsuccessful in pinning down the heavy quarkonia hindered M1 radiative transitions (i.e., those radiative transitions between states with different principal quantum numbers that require one of the quarks to flip-spin) and yield predictions that are spread over a vast range. In this talk, we will learn how to accurately and...Go to contribution page
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Mr Andrew Bond (University of Sussex)25/07/2016, 18:05We will discuss some of the recent developments in understanding ultraviolet completions of gauge-Yukawa theories beyond traditional asymptotic freedom.Go to contribution page
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Mr Fabian Hutzler (University Regensburg)25/07/2016, 18:05We present results of the first ab initio lattice QCD calculation of the normalization constants and first moments of the leading twist distribution amplitudes of the full baryon octet, corresponding to the small transverse distance limit of the associated S-wave light-cone wave functions. The P-wave (higher twist) normalization constants are evaluated as well. The calculation is done using...Go to contribution page
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Dr Tobias Hartung (King's College London)25/07/2016, 18:05In lattice QFT, we are often presented with integrals over polynomials of coefficients of matrices in $U(N)$ or $SU(N)$ with respect to the Haar measure. In some physical situations, e.g., in presence of a chemical potential, these integrals are, however, numerically very difficult since they are highly oscillatory which manifests itself in form of the sign problem. In these cases, Monte Carlo...Go to contribution page
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Mr Ryoichiro Ueno (Graduate School of Science, Hiroshima University)25/07/2016, 18:05We calculate the $\Lambda$-parameter in $\overline{\mathrm{MS}}$ scheme for SU(3) pure gauge theory with the twisted gradient flow method non-perturbatively. Using the Schrödinger functional scheme as an intermediate scheme, we numerically evaluate the $\Lambda$-parameter ratio...Go to contribution page
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Mr Michele Mesiti (University of Pisa and INFN - Sezione di Pisa)25/07/2016, 18:05In this talk I will report on our recent results about the determination of the position and the nature of the Roberge-Weiss endpoint. Our study is performed in $N_f=2+1$ QCD, with physical quark masses, making use of stout-improved staggered fermions and of the tree level Symanzik...Go to contribution page
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David Y.-J. Chu (Department of Electrophysics, National Chaio Tung University)25/07/2016, 18:25We study the scaling property of Higgs-Yukawa models. Using the technique of Finite-Size Scaling, we are able to derive formulae to describe the behaviour of the observables near the Gaussian fixed point. The renormalisation procedure is discussed in this talk. A feasibility study of our strategy is performed for pure scalar theory. In addition, we test the formulae with lattice data...Go to contribution page
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Masanori Hanada (Kyoto U, Stanford U)25/07/2016, 18:25We argue that a small, quantum black hole can be made from atoms and lasers. The holographic principle claims that the quantum gravitational systems, e.g. superstring theory, is equivalent to non-gravitational quantum systems, e,g. super Yang-Mills theory. Here the 'equivalence' means two theories cannot be distinguished even in principle. Therefore, if the holographic principle is true,...Go to contribution page
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Prof. Christian Fischer (JLU Giessen)25/07/2016, 18:25I will give an overview on our recent results for the phase diagram of QCD with Nf=2+1 and Nf=2+1+1 flavors. We use a combination of lattice and Dyson-Schwinger methods to determine the chiral and deconfinement order parameters at finite temperature and chemical potential. In a recent exploratory study we also give a first estimate on the influence of baryon effects on the location of...Go to contribution page
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Mr Michael Gruber (RQCD collaboration)25/07/2016, 18:25Octet baryon distribution amplitudes are non-perturbative objects of phenomenological interest parametrizing the momentum distribution within the corresponding Fock states. Their normalization and their moments can be calculated using lattice QCD, and such results require renormalization. However, the MS-bar scheme, i.e., the renormalization scheme used in phenomenological applications,...Go to contribution page
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Prof. Gerrit Schierholz (DESY)25/07/2016, 18:25The running coupling constant $\alpha_s(Q^2)$ is computed from the Wilson flow for three quark flavors on multiple volumes and a wide range of lattice spacings, which allows for a continuum extrapolation. Of particular interest is the behavior at small $Q^2$ and the question of an infrared fixed point.Go to contribution page
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Mr Cian O'Hara (Trinity College Dublin)25/07/2016, 18:25We present preliminary calculations towards radiative transitions in charmonium using Nf = 2+1 dynamical ensembles generated by the Hadron Spectrum Collaboration. A crucial ingredient in this work is the use of variationally optimised interpolating operators which allow for a reliable determination of the three-point correlation functions needed. Using these operators, we perform first...Go to contribution page
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Dr Laurent Lellouch (CNRS & Aix-Marseille U.)25/07/2016, 19:00The origin of mass is mysterious. In our everyday experience, the mass of an object is the sum of the mass of its parts. However, in the world of subatomic particles such as quarks and gluons, this everyday assumption is no longer true and even very small mass differences can have cosmic consequences. After an introduction to the subatomic world and the mechanisms by which mass emerges, I...Go to contribution page
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Prof. Martin Savage (Institute for Nuclear Theory)26/07/2016, 09:00Lattice QCD is making good progress toward calculating the structure and properties of light nuclei and the forces between nucleons. These calculations will ultimately refine the nuclear forces, particularly in the three- and four-nucleon sector and the short-distance interactions of nucleons with electroweak currents, and allow for a reduction of uncertainties in nuclear many-body...Go to contribution page
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Dr Michael Endres (MIT)26/07/2016, 09:45Despite the numerous successful applications of lattice QCD in nuclear and particle theory, fundamental algorithmic challenges remain. Among those, relevant for numerical studies of QCD on a space time torus, is topological freezing--a form of critical slowing down, which becomes particularly severe for lattice spacing less than 0.05 fm. In this talk, I will highlight several recently proposed...Go to contribution page
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Dr Shinji Takeda (Kanazawa University)26/07/2016, 10:15In this talk, I will review the recent progress of tensor network approaches; Hamiltonian/Hilbert-space approach and Lagrangian/path-integral approach, whose striking feature is free of the sign problem. As examples, I will show some results of CP(N-1) model including theta-term and other models. Finally, I will address outstanding problems and discuss future prospects.Go to contribution page
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Dr Sara Collins (University of Regensburg)26/07/2016, 11:15Recent calculations of hadron structure observables and related technical and theoretical advances are reviewed. A wealth of information on the properties of hadrons can be provided by lattice methods such as their wavefunctions, response to electromagnetic, weak or beyond the Standard Model probes and their internal dynamics in terms of the contributions from quarks and gluons. Progress...Go to contribution page
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Prof. Huey-Wen Lin (Michigan State University)26/07/2016, 12:00Studying the structure of nucleons is not only important to understanding the strong interactions of quarks and gluons, but also to improving the precision of new-physics searches. Since a broad class of experiments, including the LHC and dark-matter detection, require Standard-Model backgrounds with parton distribution functions (PDFs) as inputs for disentangling SM contributions from...Go to contribution page
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Dr Akaki Rusetski (HISKP, University of Bonn, Germany)26/07/2016, 14:00We propose a framework for the extraction of the $B\to K^*$ decay form factors from lattice data, based on the non-relativistic effective field theory in a finite volume. A possible admixture of the $\eta K$ channel is studied, and the multi-channel Lellouch-Luescher formula is reproduced. Further, a procedure is formulated for the extraction of the form-factors at the resonance pole. The...Go to contribution page
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Christoph Lehner (BNL)26/07/2016, 14:00I present our recent results for the disconnected HVP contribution and report the current status of our light connected HVP contribution to the muon anomalous magnetic moment.Go to contribution page
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Dr Yu Maezawa (YITP, Kyoto University)26/07/2016, 14:00We present new results on the charm and bottom quark masses as well as the strong coupling constant in 2+1-flavor QCD using Highly Improved Staggered Quark action and gauge configurations generated by HotQCD Collaboration. Our approach is based on calculating the moments of meson correlators and we use a wide range of lattice spacing up to $a^{-1} \sim 4.9$ GeV in our study. The ratios of...Go to contribution page
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Mr Felipe Attanasio (Swansea University)26/07/2016, 14:00Complex Langevin simulations have been able to successfully reproduce results from Monte Carlo methods in the region where the sign problem is mild and make predictions when it is exponentially hard. We present here our study of the QCD phase diagram in the limit of heavy and dense quarks (HDQCD) for 3 different lattice volumes and the boundary between the hadronic phase and the quark-gluon...Go to contribution page
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Daniel Nogradi (Eotvos University)26/07/2016, 14:00Numerical results are reported on the discrete $\beta$-function of $SU(3)$ gauge theory with $N_f=12$ fundamental fermions in the gradient flow scheme. Controlled continuum extrapolation is performed for $s=2\;$ scale change with $c = \sqrt{8t} / L = 0.2$ targeting 3 tuned values of the renormalized coupling, approximately $g^2=6.0,\; 6.2\;$ and $\;6.4$. Contrary to a previous claim, no...Go to contribution page
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Markus Werner (University of Bonn)26/07/2016, 14:00We present new results for $I=1 \ \pi\pi$ scattering with twisted mass fermions utilizing the sLapH method. The breaking of rotational symmetry on the lattice is fully taken into account at multiple moving frames. Our previous calculation is extended by more single and multi-hadron operators and by utilising more irreducible representations.Go to contribution page
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Dr George Fleming (Yale University)26/07/2016, 14:20The LSD Collaboration has recently completed a study of the light hadron spectrum in SU(3) gauge theory with eight light, degenerate flavors. We have observed that the lightest isosinglet scalar meson, also called the sigma, remains essentially degenerate with the pions even when the (pi,sigma) multiplet mass scale falls below half the rho meson mass as a function of the input quark mass. ...Go to contribution page
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Dr Maxim Mai (George Washington University)26/07/2016, 14:20We propose a method for the direct extraction of the complex hadron-hadron optical potential (or, equivalently, the phase shift and inelasticity in a given channel) on the lattice, which does not require the use of the multi-channel Lüscher formalism, but the knowledge of a tower of energy levels only. The approach works for any multi-particle states and tested explicitly on a set of...Go to contribution page
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Dr Krzysztof Cichy (Goethe-University Frankfurt am Main)26/07/2016, 14:20We perform a benchmark study of the step scaling procedure for the ratios of renormalization constants extracted from position space correlation functions. We work in the quenched approximation and consider the pseudoscalar, scalar, vector and axial vector bilinears. The pseudoscalar/scalar cases allow us to obtain the non-perturbative running of the quark mass over a wide range of energy...Go to contribution page
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Dr Benjamin Jaeger (Swansea University)26/07/2016, 14:20Complex Langevin methods have been successfully applied in theories that suffer from a sign problem such as HDQCD. We present and illustrate a novel method that ensures that Complex Langevin simulations stay close to the SU(3) manifold, which lead to correct and improved results in the framework of HDQCD and pure gauge simulations. Applying the same technique in fully dynamical QCD simulations...Go to contribution page
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Mr Luchang Jin (Columbia University)26/07/2016, 14:20We report our recent lattice calculation of hadronic light-by-light contribution to muon $g-2$ using our recent developed moment method. The connected diagrams and the leading disconnected diagrams are included. The calculation is performed on a $48^3 \times 96$ lattice with physical pion mass and 5.5 fm box size. We expect sizable finite volume and finite lattice spacing corrections to the...Go to contribution page
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Mr Bin Hu (Department of Physics, The George Washington University)26/07/2016, 14:20The $\rho (770)$ meson is the most extensively studied resonance in lattice QCD simulations in two ($N_f=2$) and three ($N_f=2+1$) flavors. We analyze all available phase shifts from $N_f=2$ simulations using unitarized Chiral Perturbation Theory, allowing not only for the extrapolation in mass but also in flavor, $N_f=2\rightarrow N_f=3$. The flavor extrapolation requires information from...Go to contribution page
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Mr Daniel Robaina (Institute for Nuclear Physics Mainz)26/07/2016, 14:40The Generalized Eigenvalue Problem (GEVP) has been intensively used in the past in order to reliably extract energy levels from time-dependent euclidean correlators calculated in Lattice QCD. We propose an alternative formulation of the GEVP in frequency space. Our approach consists in applying the model independent Backus-Gilbert method to a set of euclidean two-point functions with common...Go to contribution page
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Mr David Preti (Instituto de Física Teórica CSIC/UAM)26/07/2016, 14:40We present our results for the computation of the non-perturbative running of renormalized quark masses in $N_f=3$ QCD, between the electroweak and hadronic scales, using standard finite-size scaling techniques. The computation is carried out to very high precision, using massless $\mathcal{O}$(a) improved Wilson quarks. Following the strategy adopted by the ALPHA...Go to contribution page
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Dr Nicolas Garron (PU)26/07/2016, 14:40We investigate QCD at finite densities of heavy quarks from a density-of-state perspective. Using the LLR approach, we can compute the phase-factor expectation value in the strong sign problem regime with unprecedented precision due to its inherent exponential error suppression. We use our findings to draw conclusions on the approach using phase cumulants.Go to contribution page
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Mr Andrew Gasbarro (Yale University)26/07/2016, 14:40In recent years, lattice studies of multi-flavor gauge theories near and inside the conformal window have provided strong evidence for the existence of light 0++ states in their spectra, which has led to a renewed interest in strong dynamics as a solution to the Higgs hierarchy problem. An additional requirement to realize a UV complete composite Higgs sector is that observables of low energy...Go to contribution page
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Hanno Horch (University of Mainz)26/07/2016, 14:40We present results of our lattice QCD study of the hadronic vacuum polarization (HVP) function with O$(a)$-improved $N_{\rm f}=2$ Wilson fermions with twisted boundary conditions. We discuss the extraction of the leading order hadronic contribution to the anomalous magnetic moment of the muon $\left(a_\mu^{\mathrm{HLO}}\right)$ via the hybrid method involving two steps: (i) To describe...Go to contribution page
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Mr Antoni Woss (University of Cambridge)26/07/2016, 14:40Distillation is a method of smearing that allows for the efficient computation of correlation functions on the lattice. It vastly reduces the number of operations needed to calculate correlation functions with large bases of operators and all-to-all propagators. In this investigation, we provide a comprehensive comparison of the quality of extracted energy spectra with different amounts of...Go to contribution page
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Christian Rohrhofer (University of Graz)26/07/2016, 15:00We identify the chiral and angular momentum content of the leading quark-antiquark Fock component for the $\rho(770)$ and $\rho(1450)$ mesons using a two-flavor lattice simulation with dynamical Overlap Dirac fermions. We extract this information from the overlap factors of two interpolating fields with different chiral structure and from the unitary transformation between chiral and...Go to contribution page
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Ms Julia Volmer (DESY Zeuthen)26/07/2016, 15:00The error scaling for Markov Chain - Monte Carlo techniques (MC-MC) with $N$ samples behaves like $\frac{1}{\sqrt{N}}$. This scaling makes it often very time intensive to reduce the error of calculated observables, in particular for applications in lattice QCD. It is therefore highly desirable to have alternative methods at hand which show an improved error scaling. One candidate for...Go to contribution page
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Katsumasa Nakayama (Nagoya University)26/07/2016, 15:00We extract the charm quark mass and the strong coupling constant by using the charmonium current correlators with $n_f$ = 2 + 1 Mobius domain wall fermions. The temporal moments of the correlators are sensitive to short-distance physics, and could be also calculated in the continuum theory by perturbative expansion, which is known up to four- loop order.We match our lattice calculation...Go to contribution page
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Dr Yasumichi Aoki (KEK)26/07/2016, 15:00Flavor singlet pseudoscalar and scalar mesons are importat objects for both SM-QCD and technicolor models. The study utilizes the handle of the number of flavors in the many-flavor QCD simulations, which has been performed by LatKMI collaboration. Through this, implications to both SM-QCD and technicolor, which could help understand the dynamics of flavor singlet sector, are anticipated. We...Go to contribution page
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Mr Mario Giuliani (University of Graz)26/07/2016, 15:00We study new developments for the Density of States (DoS) method to simulate systems affected by the complex action problem. In particular we use the functional fit approach (FFA). It consists of a restricted Monte Carlo simulation with an additional Boltzmann factor, which allows one to explore the DoS for a given part of the spectrum. We fit the simulation data with a known function to...Go to contribution page
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Mr James Harrison (University of Southampton)26/07/2016, 15:00Lattice calculations of the leading-order hadronic contribution to the muon g-2, from the hadronic vacuum polarisation, are approaching sub-percent level precision. At this level, it becomes important to consider corrections from isospin-breaking. Here, we include quenched QED in our simulations by stochastically generating U(1) gauge configurations and combining these with existing SU(3)...Go to contribution page
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Dr Savvas Zafeiropoulos (Goethe University Frankfurt)26/07/2016, 15:20We study a Random Matrix Model for QCD at finite density via Complex Langevin dynamics. This model has a phase transition to a phase with non-zero baryon density. We study the convergence of the algorithm as a function of the quark mass and the chemical potential and focus on two main observables: the baryon density and the chiral condensate. As expected, for simulations close to the chiral...Go to contribution page
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Prof. Ting-Wai Chiu (National Taiwan University)26/07/2016, 15:20I present the updated results of the discrete $\beta$-function of the $SU(3)$ gauge theory with $N_f=10$ massless optimal domain-wall fermions in the fundamental representation. The renormalized coupling is obtained by the finite-volume gradient flow scheme on $ L^4 $ lattices, for seven lattice sizes: $ L/a = 8, 10, 12, 16, 20, 24, 32 $; and each with $11 - 17$ different lattice spacings...Go to contribution page
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Dr Raul Briceno (Thomas Jefferson National Accelerator Facillity)26/07/2016, 15:20In this talk, I present recent progress towards the determination of resonant systems via lattice QCD. The truncation of the volume -- necessary for lattice QCD calculations -- significantly alters the analytic structure of the theory. For scattering processes involving two-hadron states, this can be circumvented by utilizing formalism to map finite-volume quantities obtained onto the desired...Go to contribution page
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Ms Vera Guelpers (University of Southampton)26/07/2016, 15:20We present a strategy to calculate the leading order electromagnetic corrections to meson masses and the hadronic vacuum polarization. These corrections are computed directly through a QED perturbative expansion of the QCD+QED correlation functions. We will show some first results obtained using $N_f=2+1$ Domain Wall fermions. This calculation will be directly compared to the stochastic...Go to contribution page
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Prof. Ulli Wolff (HU Berlin)26/07/2016, 15:20We study the O(3) sigma model on a D=2 lattice with a Boltzmann weight linearized in $\beta$ on each link. While the spin formulation now suffers from a sign-problem the equivalent loop model remains positive and becomes particularly simple. By studying the transfer matrix and by performing MC simulations in the loop form we study the mass gap coupling in a step scaling analysis. The...Go to contribution page
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Mr Lukas Varnhorst (University of Wuppertal)26/07/2016, 15:20We present a determination of the corrections to Dashen's theorem and of the individual up and down quark masses from a lattice calculation based on quenched QED and $N_f=2+1$ QCD simulations with 5 lattice spacings down to $0.054 \, \mbox{fm}$. The simulations feature lattice sizes up to $6 \, \mbox{fm}$ and average up-down quark masses all the way down to their physical value. For the...Go to contribution page
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Doug Toussaint (University of Arizona)26/07/2016, 15:40[MILC collaboration} In QCD simulations at small lattice spacings the topological charge $Q$ evolves very slowly, and if this quantity is not properly equilibrated it could lead to incorrect results for physical quantities, or incorrect estimates of their errors. We use the known relation between the dependence of masses and decay constants on the QCD vacuum angle $\theta$ and...Go to contribution page
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Mr Nils Asmussen (Institut für Kernphysik, Johannes Gutenberg-Universität Mainz)26/07/2016, 15:40The anomalous magnetic moment of the muon currently shows a more than $3\sigma$ discrepancy between the experimental value and recent Standard Model predictions. The theoretical uncertainty is dominated by the hadronic vacuum polarization and the hadronic light-by-light (HLbL) scattering contributions, where the latter has so far only been fully evaluated using different models. To pave the...Go to contribution page
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Prof. Stephen Sharpe (University of Washington)26/07/2016, 15:40We report progress on extending the relativistic model-independent quantization condition for three particles to a broader class of theories, and in checking the formalism. Topics that will be touched on are: (i) the extension to include the possibility of 2->3 and 3->2 transitions and (ii) checks of the formalism by comparing to threshold expansions and to the energy shift of a three-particle...Go to contribution page
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Mr chik him Wong (University of Wuppertal)26/07/2016, 15:40We will present results on important spectroscopy problems of the sextet composite Higgs model selected from the light scalar spectrum, vector resonances, the eta’ particle of the axial anomaly, and spectroscopy analysis using a mixed action with restored chiral symmetry of valence fermions.Go to contribution page
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Dr Yuta Ito (KEK)26/07/2016, 15:40In many interesting systems, the fermion determinant becomes complex and its phase plays a crucial role in the determination of the vacuum. For instance, in finite density QCD at low temperature and high density, exotic fermion condensates are conjectured to form due to such effects. When one applies the complex Langevin method to such a complex action system naively, one cannot obtain the...Go to contribution page
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Prof. Yannick Meurice (University of Iowa)26/07/2016, 15:40We reformulate the Ising model, the O(2) model with a chemical potential and the Abelian Higgs model on a 1+1 space-time lattice using the Tensor Renormalization Group (TRG) method. The reformulation allows exact blocking and connects smoothly the classical Lagrangian approach to the quantum Hamiltonian approach. We discuss the linearization of the TRG for the Ising model near the critical...Go to contribution page
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Dr Donald SInclair (Argonne-Seville)26/07/2016, 16:30We simulate Lattice QCD with 2 light quark flavours at zero temperature and finite quark number chemical potential $\mu$. Gauge cooling is applied, along with adaptive rescaling of the updating `time' increment, to stabilize the algorithm. We see evidence for the expected transition at $\mu \approx m_N/3$ and for saturation at large $\mu$. Limitations of the method are discussed.Go to contribution page
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Dr Taichi Kawanai (Forschungszentrum Jülich (Budapest-Marseille-Wuppertal collaboration))26/07/2016, 16:30Recent phenomenological and lattice determinations of the anomalous magnetic moment of the muon $a_\mu$ hint at beyond the Standard Model physics on the 3-4 sigma level. Here we present lattice results for the leading order hadronic contribution of $a_\mu$ obtained from 2+1+1 flavor, staggered quark simulations at the physical point. The various quark flavor contributions, together with their...Go to contribution page
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Mr Christopher Helmes (HISKP Universität Bonn)26/07/2016, 16:30We present results for the interaction of two Kaons at maximal isospin. The calculation is based on 2+1+1 flavour gauge configurations generated by the ETM Collaboration featuring pion masses ranging from about 230 MeV to 450 MeV at three values of the lattice spacing. The elastic scattering length $a_0$ is calculated at several values of the bare strange quark and light quark masses....Go to contribution page
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Ms Barbara De Palma (Istituto Nazionale di Fisica Nucleare (INFN) and Università di Pavia)26/07/2016, 16:30We report lattice simulations of $\phi^4_2$ and $O(N)\,\phi^4$ models, performed by means a Monte Carlo method based on the all-order strong coupling expansion (worm algorithm). The investigation of the non–perturbative features of the $\phi^4$ continuum limit in two dimensions lead us to the result $g/\mu^2 = 11.15 \pm 0.06_{stat} \pm 0.03_{syst}$ for the critical coupling. Furthermore we...Go to contribution page
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Dr Syo Kamata (Keio University)26/07/2016, 16:30We investigate the two-dimensional $\mathcal{N}=(2,2)$ supersymmetric Yang-Mills (SYM) theory on the discretized curved space both from theoretical and numerical points of view. We first show that the number of the supersymmetry of the continuum $\mathcal{N}=(2,2)$ SYM theory on any curved manifold is enhanced to two by considering an appropriate $U(1)$ gauge backgrounds associated with...Go to contribution page
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Dr Hidenori Fukaya (Osaka University)26/07/2016, 16:30We propose a 6-dimensional lattice regularization of chiral gauge theories. In our formulation, Weyl fermions are localized on the junction of two different domain-walls. One domain-wall naturally exhibits the Stora-Zumino chain of the anomaly descent equations. Another domain-wall mediates a similar inflow of the global anomalies. The anomaly free condition is equivalent to requiring the...Go to contribution page
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Jozef Dudek (Jefferson Lab)26/07/2016, 16:50We present the first calculation of coupled-channel meson-meson scattering in the isospin $=1$, $G$-parity negative sector, with channels $\pi \eta$, $K\overline{K}$ and $\pi \eta'$, in a first-principles approach to QCD. From the discrete spectrum of eigenstates in three volumes extracted from lattice QCD correlation functions we determine the energy dependence of the $S$-matrix, and find...Go to contribution page
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Dr Kohtaroh Miura (Centre de Physique Theorique, Aix-Marseille Universite, BMW Collaboration)26/07/2016, 16:50The low, euclidean momentum behavior of the hadron vacuum polarization (HVP) is critical for determining, amongst other quantities, the anomalous magnetic moments of the electron and the muon. Here we present lattice QCD results for the first few moments of the HVP obtained from 2+1+1 flavor, staggered-quark simulations at the physical point. The various quark-flavor contributions, together...Go to contribution page
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Ms Emilie Huffman (Duke University)26/07/2016, 16:50We solve a variety of sign problems for models in lattice field theory using the Hamiltonian formulation, including Yukawa models and simple lattice gauge theories. The solutions emerge naturally in continuous time and use the dual representation for the bosonic fields. These solutions allow us to construct quantum Monte Carlo methods for these problems. The methods could provide an...Go to contribution page
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Prof. Gert Aarts (Swansea University)26/07/2016, 16:50In the complex Langevin approach to lattice simulations at nonzero density, zeroes of the fermion determinant lead to a meromorphic drift and hence a need to revisit the theoretical justification. In this talk we discuss how poles in the drift affect the formal justification of the approach and then explore the various possibilities in simple models. The implications of the findings for heavy...Go to contribution page
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Prof. Joel Giedt (Rensselaer Polytechnic Institute)26/07/2016, 16:50Formulations of lattice supersymmetry over the last decade have been able to significantly reduce the amount of fine-tuning necessary in order to obtain the correct continuum limit. In the case of N=4 super Yang-Mills, the approach that has emerged as the best path forward is based on a topological twisting of the theory. Montonen and Olive found evidence that a duality could exist in...Go to contribution page
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Mr Ryo Yamamura (Osaka U.)26/07/2016, 16:50We propose a 6-dimensional lattice regularization of chiral gauge theories. In our formulation, Weyl fermions are localized on the junction of two different domain-walls. One domain-wall naturally exhibits the Stora-Zumino chain of the anomaly descent equations. Another domain-wall mediates a similar inflow of the global anomalies. The anomaly free condition is equivalent to requiring the...Go to contribution page
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Mr Alessandro Nada (Università di Torino & INFN, Torino)26/07/2016, 17:10Jarzynski's equality is a well-known result in statistical mechanics, relating free-energy differences between equilibrium ensembles with fluctuations in the work performed during non-equilibrium transformations from one ensemble to the other. In this talk, an extension of this relation to lattice gauge theory will be presented, along with numerical results for the $Z_2$ gauge model in three...Go to contribution page
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Mr Jishnu Goswami (IIT Kanpur)26/07/2016, 17:10Minimally doubled fermions(MDF) having only two species could be promising formalism to study chiral fermion on a lattice. The action being ultra-local, one expects that the MDF formulations might provide computationally cheaper alternatives to the existing lattice chiral formulations. Borici-Creutz fermion is one such minimally doubled fermion formulation. In this work, we explore the...Go to contribution page
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Dr Denes Sexty (Uni Wuppertal)26/07/2016, 17:10Lattice QCD at non-vanishing chemical potential is studied using the complex Langevin equation (CLE). We compare the results with multi-parameter reweighting both from μ=0 and phase quenched ensembles. A good agreement is found for lattice spacings below ≈0.15 fm. On coarser lattices the complex Langevin approach breaks down. Four flavors of staggered fermions are used on Nt=4,6 and 8...Go to contribution page
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David Schaich (Syracuse University)26/07/2016, 17:10I will present results from numerical studies of maximally supersymmetric Yang--Mills theory, focusing on the scaling dimension of the Konishi operator. Working with a lattice formulation that exactly preserves one supersymmetry at non-zero lattice spacing, we employ an improved action developed in 2015 that dramatically reduces lattice artifacts. Using this new improved action we are...Go to contribution page
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Dr Liuming Liu (University of Bonn)26/07/2016, 17:10We present results for the $\pi\pi$ isospin-0 scattering length calculated in twisted mass lattice QCD. We use a set of $N_f = 2 + 1 + 1$ ensembles with pion mass varying in the range of 230MeV - 510MeV at three different values of lattice spacing and two $N_f=2$ ensembles with one pion mass at its physical value and one at 250MeV. The quark disconnected diagrams are computed with...Go to contribution page
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Mr Spraggs Matthew (University of Southampton)26/07/2016, 17:10I present our work on the leading strange and charm quark-connected contributions to the muon anomalous magnetic moment using RBC/UKQCD physical point domain wall fermion ensembles.Go to contribution page
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Dr Roberto Pellegrini (The University of Edinburgh)26/07/2016, 17:30The LLR algorithm is a recent proposal for computing the density of states in lattice gauge theory. This algorithm has been tested in several bosonic models at zero and finite chemical potential with impressive results. Its original formulation is based on the simulation of the theory on restricted action intervals using local Monte Carlo updates.I will discuss a new version of the method...Go to contribution page
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Sasa Prelovsek (University of Ljubljana)26/07/2016, 17:30The operators for simulating the scattering of two hadrons with spin will be presented. Three methods give consistent operators for PN, PV, VN and NN scattering, where P, V and N denote pseudoscalar, vector and nucleon. Explicit expressions for all irreducible representations and few lowest momenta will be shown as an example. Correct transformation properties will be demonstrated.Go to contribution page
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Dr Tomomi Ishikawa (RIKEN BNL Research Center)26/07/2016, 17:30In recent years, the quasi parton distribution has been introduced to extract the parton distribution functions by the lattice QCD simulation. The quasi and standard distribution share the same collinear IR singularity and the quasi distribution can be factorized into the standard distribution with perturbative matching factor. The quasi parton distribution is known to have power-law UV...Go to contribution page
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Shinji Shimasaki (Keio University)26/07/2016, 17:30The complex Langevin method (CLM) is a promising way to perform the path integral with a complex action based on a stochastic equation for complexified dynamical variables. It is known, however, that the CLM gives wrong results in some cases, while it works, for instance, in finite density QCD in the deconfinement phase or in the heavy dense limit. In this talk, we revisit this issue starting...Go to contribution page
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Prof. Roberto Frezzotti (University of Rome Tor Vergata, Physics Department and INFN - Sezione di Roma Tor Vergata)26/07/2016, 17:30We show that maximally twisted mass fermions can be employed to regularize on the lattice the fully unquenched QCD+QED theory with vanishing theta-term. We discuss how the critical mass of the up and down quarks can be conveniently determined beyond the electroquenched approximation by imposing that certain symmetries of continuum QCD+QED, which are broken by Wilson terms, are restored (up...Go to contribution page
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Mr Daniel August (Friedrich Schiller University Jena)26/07/2016, 17:30Albeit the standard model is the most successful model of particles physics, it still has some theoretical shortcomings, for instance the hierarchy problem, the absence of dark matter, etc. . Supersymmetric extensions of the standard model could be a possible solution to these problems. One of the building blocks of these supersymmetric models are supersymmetric gauge theories. It is...Go to contribution page
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Dr Anosh Joseph (University of Cambridge)26/07/2016, 17:50Maximally supersymmetric Yang-Mills theory in five dimensions has generated a lot of interest in the recent years. It takes part in the gauge-gravity duality and its finite temperature properties have been investigated recently in the planar limit. This theory is also interesting through its conjectured relationship to the six-dimensional (2,0) theory, which is still controversial. In this...Go to contribution page
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Dr Keitaro Nagata (KEK)26/07/2016, 17:50The complex Langevin method is a promising approach to complex action systems, which suffer from the sign problem. In particular, the use of gauge cooling enabled the studies of finite density QCD either in the deconfined phase or in the heavy dense limit. In the confined phase with light quarks, however, the method does not work as it is due to the singularities in the fermion drift...Go to contribution page
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Prof. Ying Chen (Institute of High Energy Physics, CAS)26/07/2016, 17:50The glueball spectrum is investigated through a $N_f=2$ lattice QCD study. The gauge configurations are generated with two degenerate flavors of quarks on anisotropic lattices. At two pion masses, say, $m_\pi=580$ MeV and $920$ MeV, we obtain the masses of the scalar, the tensor glueballs, which are in agreement with the results from the previous quenched and unquenched lattice QCD studies....Go to contribution page
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Prof. Biagio Lucini (Swansea University)26/07/2016, 17:50It has been shown that the recently proposed LLR method is very efficient at overcoming strong metastabilities that arise near first-order phase transition points. Here we present a systematic study of the performance of the algorithm near (pseudo)critical points on q-state Potts models for q as large as 20, in two and three dimensions. In particular, we shall focus our study on the ergodicity...Go to contribution page
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Dr Holger Perlt (Institute for Theoretical Physics, University of Leipzig)26/07/2016, 17:50A partially conserved axial vector current that satisfies the chiral Ward identity is defined nonperturbatively for improved Wilson fermions. A first application to the nucleon axial vector coupling is presented.Go to contribution page
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Venkitesh Ayyar (Duke University)26/07/2016, 17:50Previous studies of a simple four-fermion model with staggered fermions in 3d have shown the existence of an exotic quantum critical point, where one may be able to define a continuum limit of the Paramagnetic Strong Phase (or the PMS phase). We believe the existence of the critical point suggests a new mechanism for generating fermion masses. In this work we begin the search for this quantum...Go to contribution page
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Mr Francesco Sanfilippo (University of Southampton)26/07/2016, 18:10Metadynamics is a class of powerful algorithms in which the time evolution of a system is modified introducing a history-dependent potential associated with the past values of observables of choice. This has the effect of driving the system away from previously occupied states, ultimately speeding up the evolution of the system. These methods are widely used in biochemistry and computational...Go to contribution page
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Dr Jacques Bloch (University of Regensburg)26/07/2016, 18:10We introduce the reweighted complex Langevin method, which enlarges the applicability range of the complex Langevin method by reweighting the complex trajectories. In this reweighting procedure both the auxiliary and target ensembles have a complex action. We validate the method by applying it to a random matrix model for QCD and to two-dimensional strong-coupling QCD, both at nonzero chemical...Go to contribution page
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Dr pietro giudice (University of Muenster)26/07/2016, 18:10We report on our recent results regarding numerical simulations of the four dimensional, N=1 Supersymmetric Yang-Mills theory with SU(3) gauge symmetry and light dynamical gluinos.Go to contribution page
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Mr Ryo Sakai (Kanazawa University)26/07/2016, 18:10We apply the higher order tensor renormalization group to two and three dimensional lattice fermion systems. To deal with the tensor network including Grassmann numbers, higher order Grassmann tensor renormalization group (HOGTRG) is introduced. Because of its deterministic property, HOGTRG is perfectly free of the sign problem. We analyze the well-known systems such as the Gross–Neveu...Go to contribution page
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Prof. Urs Wenger (AEC University of Bern)26/07/2016, 19:00We present a local update algorithm for gauge theories with dynamical fermions which allows simulations in fixed canonical sectors. As a first application we perform canonical simulations in N=4 supersymmetric Yang-Mills quantum mechanics without a sign problem. Compared to previous studies, we obtain results with significantly better accuracy. We also discuss some aspects of the physics of...Go to contribution page
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Mr Hwancheol Jeong (Seoul National University)26/07/2016, 19:00We study quark condensates using improved staggered fermions, where zero modes of the Dirac operator give simple poles in the chiral limit. We present a new method to identify the zero modes and to subtract their contribution from the quark condensates. Meanwhile we also identify the quantum numbers of the zero modes in the staggered fermion formalism, using the spectral flow method....Go to contribution page
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Mr Sheng-Tai Li (Central China Normal University)26/07/2016, 19:00We present updated studies of chiral phase transition in $N_{f}=2+1$ QCD. Simulations have been performed with Highly Improved Staggered Quarks (HISQ) on lattices with temporal extent $N_{\tau} = 6$ at vanishing baryon chemical potential. We updated our previous study (1511.00553) by extending the temperature window from (140MeV, 150MeV) to (140MeV, 170MeV). The strange quark mass was chosen...Go to contribution page
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Prof. Pedro Bicudo (IST - LISBOA)26/07/2016, 19:00We show the flux tubes produced by static quark-antiquark, quark-quark and quark-gluon charges at finite temperature. The sources are placed in the lattice with fundamental and adjoint Polyakov loops. We compute the square densities of the chromomagnetic and chromoelectric fields above and below the phase transition. Our results are gauge invariant and produced in pure gauge SU(3). The...Go to contribution page
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Mr Attilio Cucchieri (University of São Paulo)26/07/2016, 19:00We evaluate the so-called Bose-ghost propagator in minimal Landau gauge, for the SU(2) case in four dimensions. We consider lattice volumes up to $120^4$ and physical lattice extents up to 13.5 fm. We investigate discretization effects, as well as the infinite-volume and continuum limits. A nonzero value for this quantity provides direct evidence of BRST-symmetry breaking, related to...Go to contribution page
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Thomas Rae (University of Wuppertal)26/07/2016, 19:00We present a study of the charmed meson and baryon ground state spectra on the electrically neutral subset of the BMW $N_f=2+1+1$ gauge configurations that utilise the 3-HEX smeared clover action. The analysis focuses on a systematic evaluation of the hyperfine mass splittings of the doubly charmed $J/\psi$ and $\eta_{c}$ mesons and the singly charmed $D_s^*$ and $D_s$ mesons, with the...Go to contribution page
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Dr Azusa Yamaguchi (Software Architect), Prof. Peter Boyle (University of Edinburgh)26/07/2016, 19:00Hierarchically deflated conjugate residual We present a new class of multigrid solver algorithm suitable for the solution of 5d chiral fermions such as Domain Wall fermions and the Continued Fraction overlap. Unlike HDCG \cite{arXiv:1402.2585}, the algorithm works directly on a nearest neighbour fine operator. The fine operator used is Hermitian indefinite, for example $\Gamma_5...Go to contribution page
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Mr Matthew Kirk (IPPP, Durham University)26/07/2016, 19:00We review the current status of HQE predictions for neutral meson mixing and related observables. A comparison with most recent data shows a confirmation of the HQE, but also leaves sizeable space for new physics effects. We also point out what improved lattice inputs might be most useful for unambiguously identifying new physics in mixing observables.Go to contribution page
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Mr Joni Suorsa (University of Helsinki, Helsinki Institute of Physics)26/07/2016, 19:00We study the mass anomalous dimension of SU(2) with $N_f=6$ and $N_f = 8$ in both massless and massive quark cases for a range of gauge coupling values. In the massless case we find behaviour consistent with results obtained using the Schrödinger functional method.Go to contribution page
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Mr Benjamin Jaedon Choi (Seoul National University / Lattice Gauge Theory Research Center)26/07/2016, 19:00We present results of matching factors for $Z_q$ and $Z_m$ calculated perturbatively at the one loop level with improved staggered quarks. We calculate $Z_q$ and $Z_m$ with HYP-smeared staggered quarks. Final results of $Z_q$ and $Z_m$ at $\mu = 2 \ \text{GeV}$ and $3 \ \text{GeV}$ in the $\overline{\text{MS}}$ scheme are given in tables.Go to contribution page
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Dr Marina Krstic Marinkovic (CERN)26/07/2016, 19:00The supercomputing platforms available for high performance computing based research evolve at a great rate. However, this rapid development of novel technologies requires adaptations and optimizations of the existing codes for each new machine architecture. In such context, minimizing time of efficiently porting the code on a new platform is of crucial importance. A possible solution is to...Go to contribution page
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Mr Stefan Hofmann (Unversity of Regensburg) (German)26/07/2016, 19:00We determine the masses and the pseudo-scalar decay constants of charmed mesons using non-perturbatively O($a$) improved Wilson quarks. Our analysis is based on the $N_{\rm f}=2+1$ ensembles using open boundary conditions, generated within the CLS effort. The status of results for 2 lattice spacings, $a\approx 0.086$ fm and $a\approx 0.064$ fm, will be presented. The pion mass is varied...Go to contribution page
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Prof. Tetsuya Onogi (Osaka University)26/07/2016, 19:00The relaxation time for the fermions in the magnetic field is needed for estimate the chiral magnetic effect. However, it has been estimated only in the strong magnetic field. We discuss the relaxation time away from the strong magnetic field limit.Go to contribution page
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Prof. Ken-ichi Ishikawa (Hiroshima University)26/07/2016, 19:00We investigate the nature of the chiral phase transition using the RG improved gauge action and the Wilson quark action with two degenerate quarks on $32^3\times 16$, $24^3\times 12$, and $16^3\times 8$ lattices. We introduce RG scaling relations for both the time direction and the spacial effective masses of mesons at the chiral phase transition point. Numerical results of effective...Go to contribution page
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Dr Hideo Matsufuru (High Energy Accelerator Research Organization (KEK))26/07/2016, 19:00In this work, we study SU(2) gauge theory with many flavors using the improved domain-wall fermions, which is realized by the stout-HYP link smearing and the optimal domain-wall formulation. In contrast to the standard domain-wall fermions used in the previous studies, it enables us to investigate the small fermion mass region due to the much suppressed residual mass. With the improved...Go to contribution page
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Prof. Huey-Wen Lin (Michigan State University)26/07/2016, 19:00We present a sampling of analyses concerning the gender ratio of plenary speakers during the years 2000-2016 and make comparisons with other conferences, such as the APS April meeting. Please stop by to discuss ideas for how to make our field more accessible to women and minorities. We are preparing for an in-depth survey of the lattice field and welcome any ideas or suggestions. To leave...Go to contribution page
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Prof. Weonjong Lee (Seoul National University)26/07/2016, 19:00We present results of the indirect CP violation parameter in the neutral kaon system, $\varepsilon_K$ calculated using lattice QCD inputs including $\hat{B}_K$, $\xi_0$, $V_{us}$, and $V_{cb}$.Go to contribution page
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Raza Sufian (University of Kentucky, United States)26/07/2016, 19:00We present a lattice QCD calculation of the strange quark contribution to the proton's magnetic moment and the charge radius at the physical pion mass. The finite lattice spacing and finite volume corrections are included in a global fitting on three lattices with different lattice spacings, different volumes, and three sea quark masses. We obtain the strange magnetic moment $G^s_M(0) = -...Go to contribution page
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Prof. Christine Davies (University of Glasgow)26/07/2016, 19:00We report on the HPQCD calculation of the u/d HVP contribution to a_mu, discussed in arXiv:1601.03071. This allows us to obtain a total HVP contribution from u, d, s and c quarks and including an estimate of disconnected pieces and QED and isospin effects of 666(6)(12) x 10^{-10}. Our result implies a discrepancy between the experimental determination of a_mu and the Standard Model of 3...Go to contribution page
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Mr Felix Erben (University Mainz)26/07/2016, 19:00Results are presented from an ongoing study of the $\rho$ resonance. We use the LapH-smearing approach in order to create correlator matrices involving $\rho$ and $\pi\pi$ interpolators. The study is done in a centre-of-mass frame and several moving frames. We are able to extract effective-energy levels by solving the GEVP of those correlator matrices. The initial exploratory study is being...Go to contribution page
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Mr Sungwoo Park (Seoul National University)26/07/2016, 19:00We determine hopping parameters of the Oktay-Kronfeld (OK) action for charm and bottom quarks. We use $N_f=2+1+1$ MILC HISQ ensembles (with $a\approx0.12$fm, $am_l=0.0102$, $am_s=0.0509$ and $am_c=0.635$). As a key ingredient, we compute the masses of pseudoscalar and vector mesons $B_s^{\ast}$, $D_s^{\ast}$ and their hyperfine splittings; the valence light quark is simulated with HISQ action....Go to contribution page
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Dr Shinji Takeda (Kanazawa University)26/07/2016, 19:00We will present an update on analysis of the phase structure for finite temperature QCD with 3-flavor non-perturbatively O(a) improved Wilson-Clover fermions and Iwasaki gauge action. In our previous study, it was shown that the value of kurtosis of quark condensate at the critical point tends to deviate from that of 3D Z_2 universality class when increasing the temporal lattice sizes...Go to contribution page
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Dr Igor Bogolubsky (Joint Institute for Nuclear Research)26/07/2016, 19:00We make simulations of the zero-momentum $SU(2)$ Landau gauge gluon correlator both for periodic and zero-field boundary conditions at varying $\beta$ and $L_t * L_s^3$ lattice sizes.Go to contribution page
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Ms Ouraman Hajizadeh (University of Graz)26/07/2016, 20:00G2-QCD, i.e. QCD with the gauge group SU(3) replaced by the exceptional group G(2), shares many features with SU(3). But it is accessible at finite density on the lattice, as it has no sign problem, and at the same time has a neutron. Therefore, this theory can sustain in princple neutron star. Using the equation of state for this theory from lattice simulations, we solve...Go to contribution page
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Prof. Kostas Orginos (College of William and Mary/JLAB)26/07/2016, 20:00Results of a non-perturbative determination of RI-MOM renormalization constants for smeared quark bi-linear operators are presented. These operators are smeared using the gradient flow, enabling the smearing scale to be fixed in physical units. As a result, smeared matrix elements are free of power divergences in the lattice spacing, which allows easier control of the continuum limit of...Go to contribution page
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Sara Tähtinen (University of Helsinki, Helsinki Institute of Physics)26/07/2016, 20:00It is expected that SU(2) gauge theory with Nf fundamental fermions has an infrared fixed point when Nf is between ∼ 6 and 10. We study the hadron spectrum and scale setting in SU(2) gauge field theory with Nf = 2,4,6,8 using hypercubic stout smeared Wilson-clover (HEX) action. The case Nf = 2 is QCD-like, Nf = 6 is close to the lower edge of the conformal window, and Nf=8 is inside the...Go to contribution page
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Ms Julia Kettle (University of Edinburgh)26/07/2016, 20:00I present preliminary results for Kaon Mixing Beyond the Standard Model at the physical point.Go to contribution page
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Mr Kevin Eckert (WWU Muenster)26/07/2016, 20:00We report on analysis aspects within a joint ongoing effort of the ALPHA and RQCD Collaborations to compute charmed meson masses and the leptonic decay constants $f_{{\rm D}}$ and $f_{{\rm D}_{\rm s}}$ in $(2+1)$-flavour lattice QCD, employing non-perturbatively O($a$) improved Wilson quarks and the tree-level Symanzik-improved gauge action. Our studies make use of large-volume CLS...Go to contribution page
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Mr Sebastian Schmalzbauer (Goethe-Universität Frankfurt, Universität Regensburg)26/07/2016, 20:00We present our results obtained from gauge cooled complex Langevin simulations in 1+1D QCD at non-zero densities in the strong coupling regime with unrooted staggered fermions. For small quark masses there are regions of the chemical potential where this method fails to reproduce correct results. In theses parameter ranges we studied the effect of different gauge cooling schemes on the...Go to contribution page
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Dr Ion-Olimpiu Stamatescu (I.T.P., University Heidelberg)26/07/2016, 20:00A formula expressing the fermionic determinant as an infinite product of smaller determinants is here derived and discussed. These smaller determinants are of a fixed size, independent of the size of the lattice and are indexed by loops of increasing length. The application of the formula requires convergence considerations.Go to contribution page
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Mr Marcin Szyniszewski (Lancaster University)26/07/2016, 20:00The long-range t-V model of fermions on a lattice is known to exhibit a transition between a Luttinger liquid phase and a Mott insulator phase [1]. At insulating densities, one can tailor the potential energy of the model in such a way that one forces a quantum phase transition to either another insulating charge-density-wave phase, a bond-order phase or a Luttinger liquid [2]. We show how to...Go to contribution page
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Ms Argia Rubeo (TCD (Trinity College Dublin))26/07/2016, 20:00The gradient flow provides a new class of renormalized observables which can be measured with high precision in lattice simulations. In principle this allows to improve lattice actions a la Symanzik by requiring such observables to take their continuum values already at finite lattice spacing. At lowest order of perturbation theory we here try to identify such improvement conditions...Go to contribution page
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Mr Jaehoon Leem (Seoul National University)26/07/2016, 20:00The Oktay-Kronfeld action is a highly improved version of the Fermilab action and systematically reduces heavy quark discretization effects through $\mathcal{O}(\lambda^3)$ in HQET power counting, for the heavy-light meson spectrum. To calculate $\bar{B}\rightarrow D^{(*)}\ell \bar{\nu}$ semi-leptonic form factors using Oktay-Kronfeld heavy quarks, we need to improve the heavy quark currents...Go to contribution page
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Dr YIBO Yang (university of Kentucky)26/07/2016, 20:00We employ dimension 4 operators to improve the local vector and axial vector currents, as the leading order approximation of the lattice conserved current, and then calculate the nucleon iso-vector axial coupling $g^3_A$ using overlap valence on Domain Wall Fermion sea. Using the equality of $g^3_A$ from $A_i$ and $A_4$ components of the axial-vector current as a normalization condition in...Go to contribution page
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Tereza Mendes (University of São Paulo)26/07/2016, 20:00We investigate numerically the long-distance properties of gluon and ghost propagators in Landau gauge on the lattice, for the SU(2) case. By considering electric and magnetic gluon propagators at nonzero temperature, we extract Debye screening masses and look for signs of deconfinement around the critical temperature. Our results are related to the zero-temperature behavior of...Go to contribution page
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Mr Bernhard Lang (University Regensburg)26/07/2016, 20:00Hadrons in lattice QCD are usually created employing smeared interpolators. We introduce a new quark smearing that allows us to maintain small statistical errors and good overlaps of hadronic wavefunctions with the respective ground states, also at high spatial momenta. We test this method for various physical observables see also arXiv:1602.05525v2 [hep-lat].Go to contribution page
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Mr Francesco Scardino (University of Rome "La Sapienza")26/07/2016, 20:00We introduce new extended interpolating operators made of quenched three dimensional fermions propagating in the timeslices. Such non-local operators are well behaved under renormalisation. The mass of the three 3D fermions can be tuned in a controlled way to find a better overlap of the extended operators with the states of interest. We test these operators for baryon two-point...Go to contribution page
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Mr Suman Baral (Baylor University)26/07/2016, 20:00Lattice QCD calculations of quark loop operators are extremely time-consuming to evaluate. To calculate these diagrams we use stochastic noise methods, which employ a randomly generated set of noise vectors to project out physical signals. This is done with linear equation solvers like GMRES-DR (Generalized Minimum RESidual algorithm-Deflated and Restarted) for the first noise, and GMRES-Proj...Go to contribution page
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Dr Hiroshi Ohki (RIKEN BNL Research Center), Sergey Syritsyn (Jefferson Lab)26/07/2016, 20:00We present a progress report on the study of the CP violation effects on the nucleon from the quark chromoelectric dipole moment (cEDM) operator using $N_f=2+1$ dynamical Domain-Wall fermions. Details of the calculation and preliminary results for $m_\pi = 170$ and 250 MeV will be reported.Go to contribution page
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Dr Takashi UMEDA (Hiroshima Univ.)26/07/2016, 20:00We study scaling behavior of a chiral order parameter in the low density region, performing a simulation of two-flavor lattice QCD with improved Wilson quarks. It have been confirmed that the scaling behavior of the chiral order parameter defined by a Ward-Takahashi identity agrees with the scaling function of the three-dimensional O(4) spin model at zero chemical potential. We discuss...Go to contribution page
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Mr Eduardo Ibanez Bribian (Instituto de Fisica Teorica UAM-CSIC)26/07/2016, 20:00We present our ongoing computation of the running of the twisted Yang-Mills coupling using gradient flow techniques. In particular, we use the gradient flow equation with twisted boundary conditions to perform a perturbative expansion of the expectation value of the Yang-Mills energy density up to fourth order at finite flow time, and regularise the respective resulting sums and integrals....Go to contribution page
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Mr Peter Georg (University of Regensburg)26/07/2016, 20:00On many parallel machines, the time LQCD applications spend in communication is a significant contribution to the total wall-clock time, especially in the strong-scaling limit. We present a novel high-performance communication library that can be used as a de facto drop-in replacement in existing software. Its lightweight nature that avoids some of the unnecessary overhead introduced by MPI...Go to contribution page
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Dr Daniel Mohler (Helmholtz-Institut Mainz)26/07/2016, 20:00We use a combination of quark-antiquark and $B^{(*)}K$ interpolating fields to predict the mass of two QCD bound states below the $B^*K$ threshold in the quantum channels $J^P=0^+$ and $1^+$. The mesons correspond to the b-quark cousins of the $D_{s0}^*(2317)$ and $D_{s1}(2460)$ and have not yet been observed in experiment, even though they are expected to be found by LHCb. In addition to...Go to contribution page
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Ms Aya Kagimura (Osaka University)26/07/2016, 20:00The chiral magnetic effect (CME) is the quantum anomaly related electric charge transport phenomenon along the external magnetic field, which appears in various systems possessing chiral fermions, such as the quark-gluon plasma, condensed matter physics and astrophysics. The magnetic field dependence of the relaxation time is needed to compare the theory and experiments quantitatively....Go to contribution page
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Dr Nikhil Karthik (Florida International University)27/07/2016, 09:00There are plausibility arguments that QED in three dimensions has a critical number of flavors of massless two-component fermions, below which scale invariance is broken by the presence of bilinear condensate. We present numerical evidences from our dynamical lattice simulations using overlap as well as Wilson-Dirac fermions for the absence of bilinear condensate using the following...Go to contribution page
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Stefan Schaefer (NIC, DESY)27/07/2016, 09:00The numerical computation of many hadronic correlation functions is exceedingly difficult due to the exponentially decreasing signal-to-noise ratio with the distance between source and sink. Multilevel integration methods, using independent updates of separate regions in space-time, are known to be able to solve such problems but have so far been available only for pure gauge theory. We...Go to contribution page
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Dr Jon Bailey (Seoul National University)27/07/2016, 09:00The Oktay-Kronfeld action is a highly improved version of the Fermilab action and systematically reduces heavy quark discretization effects through $\mathcal{O}(\lambda^3)$ in HQET power counting, for the heavy-light meson spectrum. To calculate $\bar{B}\rightarrow D^{(*)}\ell \bar{\nu}$ semi-leptonic form factors using Oktay-Kronfeld heavy quarks, we need to improve the heavy quark currents...Go to contribution page
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Dr Jochen Heitger (University of Muenster, ITP)27/07/2016, 09:00Based on a non-perturbative matching strategy between Heavy Quark Effective Theory (HQET) at O(1/m) and finite-volume QCD, we report on our determination of the effective theory parameters of all components of the HQET heavy-light axial and vector currents in two-flavour lattice QCD. These parameters, which can be fixed by matching conditions between suitable QCD and HQET observables evaluated...Go to contribution page
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Susanne Ehret (University of Edinburgh)27/07/2016, 09:00The Wilson flow is a promising tool to study strongly coupled theories. Its remarkable renormalisation properties allow for a meaningful formulation of the energy-momentum tensor on the lattice. The non-perturbative computation of the latter can in turn be used to study the scaling behaviour of quantum field theories. We extent recent studies on the renormalisation of the energy-momentum...Go to contribution page
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Dr Christian Schmidt (Universitaet Bielefeld)27/07/2016, 09:00Non-perturbative lattice QCD calculations at non-vanishing baryon number density are hampered by the sign problem. The path integral becomes highly oscillating and standard Monte Carlo techniques seize working. One possible solution is the Lefschetz thimble approach. It requires a deformation of the original integration domain into a manifold embedded in complex space. For properly...Go to contribution page
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Mr Judd Harrison (Department of applied mathematics and theoretical physics, University of Cambridge)27/07/2016, 09:20We present our recent calculation of the zero-recoil form factor for the semileptonic decay $\bar{B}^0\rightarrow D^{*+} \ell^- \bar{\nu} $ using lattice QCD with 2+1+1 flavours of highly improved staggered quarks in the sea (the MILC HISQ configurations) and using non-relativistic QCD for the bottom quark. We obtain $\mathcal{F}(1)$ and combine this with the latest HFAG average of $\eta_{EW}...Go to contribution page
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Marco Cè (Scuola Normale Superiore, Pisa, Italy & INFN, Sezione di Pisa, Italy)27/07/2016, 09:20The numerical computation of many hadronic correlation functions is exceedingly difficult due to the exponentially decreasing signal-to-noise ratio with the distance between source and sink. Multilevel integration methods, using independent updates of separate regions in space-time, are known to be able to solve such problems but have so far been available only for pure gauge theory. We...Go to contribution page
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Dr Paul Rakow (University of Liverpool)27/07/2016, 09:20When QED is added to QCD simulations we have to consider the effects of massless degrees of freedom (the photons), which bring new problems which we did not have to worry about in simulations of pure QCD. Related to this, we have questions about the boundary conditions - how can we reconcile periodic boundary conditions with Gauss's Law? What is the best way of treating zero modes of the...Go to contribution page
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Dr Yuya Tanizaki (RIKEN BNL Research Center)27/07/2016, 09:20Path integral on Lefschetz thimbles gets much attention in the context of the sign problem, because of its usefulness in order to study the system with the complex classical action nonperturbatively. After giving its brief introduction, it is applied for studying the sign problem of the one-site Hubbard model. This model has a severe sign problem, which looks quite similar to that of the...Go to contribution page
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Dr Stefano Piemonte (University of Regensburg)27/07/2016, 09:20We report on our studies of the renormalization of flavor singlet quark bilinear operators in lattice QCD. The renormalization constants are determined non-perturbatively using gauge field ensembles with Nf=2 dynamical clover improved fermions. The renormalization is performed in the RI-MOM and RI-SMOM schemes. The difference between flavor singlet and non-singlet quark bilinear operators is...Go to contribution page
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Mr Francesco Capponi (Plymouth University)27/07/2016, 09:20We present an update about our program for the non perturbative renormalization of the energy momentum tensor. Our strategy consists in probing suitable lattice Ward identities with observables computed along the gradient flow. This set of identities exhibits many interesting qualities, arising from the UV finiteness of flowed composite operators, and can be used to measure the renormalization...Go to contribution page
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Dr Andrew Lytle (University of Glasgow)27/07/2016, 09:40We use both non-relativistic QCD (NRQCD) and fully relativistic formalisms to calculate semileptonic form factors for the decays B_c -> eta_c lv and B_c -> J/psi lv over the entire q^2 range. To achieve this we employ a highly improved lattice quark action at several lattice spacings down to a=.044 fm, which allows a fully relativistic treatment of charm and simulation of the full q^2 range...Go to contribution page
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Dr Ross Young (University of Adelaide)27/07/2016, 09:40Using dynamical lattice simulations of the coupled theory of QED and QCD we explore some particular aspects of the periodic boundary conditions. We observe that the finite volume effects in spectroscopy are dependent upon the precise implementation of the gauge-fixing condition. We also report on the finite-volume dependence of the charge renormalisation.Go to contribution page
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Dr Georg von Hippel (University of Mainz)27/07/2016, 09:40We report on the determination of the renormalization factors of quark bilinears which are required among others in order to determine the nucleon scalar and tensor charges from the CLS $N_f=2$ configurations. Working in the RI'-MOM scheme, we eliminate all lattice artifacts at one-loop order using a combination of analytical results near the continuum limit and numerical calculations in...Go to contribution page
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27/07/2016, 09:40
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Dr Matthias Rottmann (University of Wuppertal)27/07/2016, 09:40In this talk we report on the publication of the DDalphaAMG solver library. We describe its features, show examples of its application and give an overview of future developments.Go to contribution page
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Dr Mattia Dalla Brida (DESY - Zeuthen)27/07/2016, 09:40The perturbative calculation of gradient flow observables is technically challenging. Current results are in fact limited to a few quantities and, in general, to low perturbative orders. Numerical stochastic perturbation theory is a potentially powerful tool that may be applied in this context. Precise results using these techniques, however, require control over both statistical and...Go to contribution page
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Dr Chris Monahan (Rutgers, the State University of New Jersey)27/07/2016, 10:00We present a calculation of the form factors, $f_0$ and $f_+$, for the $B_{(s)}$ to $D_{(s)}$ semileptonic decays. Our work uses the MILC $n_f=2+1$ asqtad configurations with NRQCD and HISQ valence quarks at four values of the momentum transfer $q^2$. We present preliminary results for our combined chiral-continuum extrapolation.Go to contribution page
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Mr Simone Bacchio (University of Cyprus - University of Wuppertal)27/07/2016, 10:00We extend the Adaptive Aggregation Based Domain Decomposition Multigrid (DD-$\alpha$AMG) algorithm to $N_f=2$ twisted mass fermions. We show numerical results for an $N_f=2$ ensemble of twisted fermions with a clover term simulated at the physical value of the pion mass. We fine-tuned the parameters to achieve a speedup comparable to the one obtained for clover fermions. We also present a...Go to contribution page
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Ms Dorota Grabowska (INT/UW)27/07/2016, 10:00I discuss continuing work on a recent proposal for the nonperturbative regulator for chiral gauge theories which combines domain wall fermions and gradient flow, Phys.Rev.Lett. 116 (2016) 211602. Implementing chiral gauge theories on the lattice requires not only decoupling mirror fermions to allow for fermions in complex representations, but also a road to failure for theories with fermions...Go to contribution page
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Mr Daniel Schmidt (Friedrich Schiller University Jena)27/07/2016, 10:00We investigate a class of quantum field theories of fermions interacting by a quartic coupling. This includes well-known models like the Gross-Neveu model and the Thirring model. In three spacetime dimensions, these models are used to describe properties of solid state systems like high temperature superconductors and graphene. Additionally, they are interesting as toy models to study...Go to contribution page
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Dr Piotr Korcyl (University of Regensburg)27/07/2016, 10:00We determine quark mass dependent order a improvement terms of the form $b_J$ am for non-singlet scalar, pseudoscalar, vector and axialvector currents, using correlators in coordinate space. We use a set of CLS ensembles comprising non-perturbatively improved Wilson Fermions and the tree-level Luescher-Weisz gauge action at $\beta=3.4, 3.46, 3.55$ and $\beta=3.7$, corresponding to lattice...Go to contribution page
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Dr Francesco Di Renzo (University of Parma & INFN)27/07/2016, 10:00Monte Carlo simulations of lattice quantum field theories on Lefschetz thimbles are non trivial. We discuss a new Monte Carlo algorithm based on the idea of computing contributions to the functional integral which come from complete flow lines. The latter are the steepest ascent paths attached to critical points, i.e. the basic building blocks of thimbles. The measure to sample is thus...Go to contribution page
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Ms Ava Khamseh (The University of Edinburgh)27/07/2016, 10:20A new renormalization scheme is defined for fermion bilinears in QCD at non vanishing quark masses. This new scheme, denoted RI/mSMOM, preserves the benefits of the nonexceptional momenta introduced in the RI/SMOM scheme, and allows a definition of renormalized composite fields away from the chiral limit.Go to contribution page
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Dr Hiromichi Nishimura (RIKEN BNL Research Center)27/07/2016, 10:20We consider the spectrum of transfer matrix eigenvalues associated with Polyakov loops in lattice QCD at strong coupling. The transfer matrix at finite density is non-Hermitian, and its eigenvalues become complex as a manifestation of the sign problem. We show that the symmetry under charge and complex conjugations ensures that the eigenvalues are either real or part of a complex conjugate...Go to contribution page
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Mr David Murphy (Columbia University)27/07/2016, 10:20As algorithmic developments have driven down the cost of simulating degenerate light quark pairs the relative cost of simulating single quark flavors with the Rational Hybrid Monte Carlo (RHMC) algorithm has become more expensive. TWQCD has proposed an exact one-flavor algorithm (EOFA) that allows for HMC simulations of a single quark flavor without taking a square root of the fermion...Go to contribution page
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Prof. Richard Richard Brower (Boston University)27/07/2016, 10:20A Quantum Finite Element (QFE) Lagrangian is formulated for a general simplicial complex approximation to a smooth Euclidean Riemann manifold. The construction is applied to Wilson Dirac fermions with the appropriate lattice spin connection and to phi 4th-theory with QFE counter terms required for these theories to converge in the continuum limit. Numerical tests are given for the...Go to contribution page
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Mr Andrey Kotov (ITEP)27/07/2016, 10:20Dirac semimetals are recently discovered materials with low energy spectrum similar to the massless two flavour 3+1D Dirac fermions. The interaction between quasiparticles in Dirac semimetals is instantaneous Coulomb with large effective coupling constant \alpha\sim 1. In this report we present the result of study of the phase diagram of Dirac semimetals within lattice simulation with...Go to contribution page
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Dr Oliver Witzel (University of Edinburgh)27/07/2016, 10:20First results for our calculation of semi-leptonic $B$ decays with charmed-mesons in the final state are presented. Our work is based on RBC-UKQCD's 2+1 flavor domain-wall fermion and Iwasaki gauge field configurations, We calculate the form factors by simulating the $b$ quarks using the relativistic heavy quark action, create light $u/d$ and $s$ quarks with standard domain-wall kernel, and...Go to contribution page
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Mr Andrea Bussone (Univeristy of Southern Denmark & CP3 Origins)27/07/2016, 10:40We present a cheap strategy to optimize Hybrid Monte Carlo parameters in simulations of QCD and QCD-like theories. We specialize to the case of mass-preconditioning, with multiple-time-step Omelyan integrators. Starting from properties of the shadow Hamiltonian we show how the optimal setup for the integrator can be chosen once the forces and their variances are measured, assuming that...Go to contribution page
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Dr Matthew Wingate (University of Cambridge)27/07/2016, 10:40The width difference $\Delta \Gamma_s$ is one of three observables, along with the mass splitting $\Delta M_s$ and the semileptonic CP asymmetry $a^s_{\mathrm{SL}}$, whose measurements completely constrain the physics of $B_s-\bar{B}_s$ oscillations. One of the dominant uncertainties in theoretical calculations of the width difference is due to not knowing matrix elements of...Go to contribution page
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Prof. Lorenz von Smekal (Justus-Liebig University Giessen)27/07/2016, 10:40We study the phase diagram of the fermionic Hubbard model on the hexagonal lattice in the space of on-site and nearest neighbor couplings with Hybrid-Monte-Carlo simulations. With pure on-site repulsion this allows to determine the critical coupling strength for spin-density wave formation. We compare the standard approach of introducing a small mass term, explicitly breaking the sublattice...Go to contribution page
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Asobu Suzuki (University of Tsukuba)27/07/2016, 10:40Canonical approach is one of the powerful tools to approach the QCD phase diagram. We calculate the canonical partition function instead of the grand canonical one in the canonical approach. However, it is known that the sign problem emerges as a complex phase of the canonical partition function. Thanks to multi-precision calculations with the canonical approach we obtained the canonical...Go to contribution page
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Dr Andreas Athenodorou (University of Cyprus)27/07/2016, 11:30We perform a numerical comparison of different lattice definitions of the topological charge by investigating the correlation coefficient between different definitions as well as the topological susceptibility. We use small-volume ensembles with 2 flavours of dynamical twisted mass fermions. We investigate the following definitions of the topological charge: index of the overlap Dirac...Go to contribution page
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Mr Masaaki Tomii (SOKENDAI)27/07/2016, 11:30We calculate the current correlators in the coordinate space and compare them with the experimental information obtained through the spectral functions of hadronic tau decays at ALEPH. Lattice data are obtained with 2+1 Mobius domain-wall fermions at three lattice spacings 0.044, 0.055 and 0.080 fm and the continuum limit is taken. On the experimental side, there is no information for...Go to contribution page
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Prof. Kazuyuki Kanaya (CiRfSE, Univ. Tsukuba)27/07/2016, 11:30The energy-momentum tensor and the equation of state are studied in finite-temperature (2+1)-flavor QCD with improved Wilson quarks, using the gradient flow method proposed by Makino and Suzuki. Although the up and down quarks are heavy yet ($m_{\rm PS}/m_V \approx 0.63$), we obtain reasonable results, suggesting that the method works well. We also report on the results on the chiral...Go to contribution page
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Dr Meifeng Lin (Brookhaven National Laboratory)27/07/2016, 11:30We present updated strategies and results of combining hand-tuning with the R-Stream source-to-source auto-parallelizing compiler to transform the serial implementation of the domain wall fermion Dslash kernel in CPS into an efficient parallel code targeting the Intel Xeon CPUs. The R-Stream compiler performs preliminary optimizations of the input Dslash code, including a novel iteration space...Go to contribution page
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amarjit soni (BNL)27/07/2016, 11:30We investigate the possibility that the dark matter candidate is from a pure non-abelian gauge theory of the hidden sector, motivated in large part by its elegance and simplicity. The dark matter is the lightest bound state made of the confined gauge fields, the hidden glueball. We point out this simple setup is capable of providing rich and novel phenomena in the dark sector, especially in...Go to contribution page
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Prof. Margarita Garcia-Perez (Instituto de Fisica Teorica UAM-CSIC)27/07/2016, 11:30We derive the perturbative expansion of Wilson loops to order g^4 in a SU(N) lattice gauge theory with twisted boundary conditions. Our expressions show that the thermodynamic limit is attained at infinite N for any number of lattice sites and allow to quantify the deviations from volume independence at finite large N as a function of the twist. The effect of adjoint Wilson fermions will be...Go to contribution page
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Eduardo Royo (Universidad de Zaragoza)27/07/2016, 11:50Understanding the role of the $\theta$ parameter in QCD and its connection with the strong CP problem and axion physics is one of the major challenges for high energy theorists. Due to the sign problem, at present only the QCD topological susceptibility is well known. Using an algorithmic approach that could potentially be extended to QCD, we study as a first step the $\theta$-dependence...Go to contribution page
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Mr Arjun Gambhir (College of William and Mary/JLab)27/07/2016, 11:50Computing disconnected diagrams on the lattice involves taking the trace of the inverse of the Dirac operator. This is a computationally challenging problem, however recent algorithmic improvements such as low mode averaging and hierarchical probing have increased the efficiency of this trace estimation. We detail an algorithm that builds upon hierarchical probing by deflating the near null...Go to contribution page
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Randy Lewis (York University)27/07/2016, 11:50SU(2) gauge theory with a single fermion in the fundamental representation is a minimal non-Abelian candidate for the dark sector. Having only a single flavor provides a natural mechanism for stabilizing dark matter on cosmological timescales. Preliminary lattice results will be presented and discussed in the context of dark matter phenomenology.Go to contribution page
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Dr Nazario Tantalo (Rome University Tor Vergata and INFN sez. of Rome Tor Vergata)27/07/2016, 11:50In Ref.[1] we proposed a method for calculating leptonic (and semileptonic) decay rates of pseudoscalar mesons including $O(\alpha)$ electromagnetic corrections. Because of the presence of infrared divergences, this requires the calculation of contributions with both virtual and real photons. We have shown that the real photon contribution, by integrating up to photon momenta of the order of...Go to contribution page
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Prof. Masanori Okawa (Hiroshima University)27/07/2016, 11:50Meson masses and decay constants in the large N limit of SU(N) gauge theory is estimated from the twisted space-time reduced model. To this end, we introduce a new smearing method which enables us to obtain reliable values for these quantities.Go to contribution page
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Ms Jana Günther (University of Wuppertal)27/07/2016, 11:50An efficient way to study the QCD phase diagram at small finite density is to extrapolate thermodynamical observables from imaginary chemical potential. In this talk we present results on several observables for the equation of state to order (muB/T)^6. The observables are calculated along the isentropic trajectories in the (T, muB ) plane corresponding to the RHIC Beam Energy Scan collision...Go to contribution page
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Prof. Antonio Gonzalez-Arroyo (Instituto de Fisica Teorica UAM/CSIC)27/07/2016, 12:10We use a recently formulated expression for computing meson masses at large N to study the spectrum of two-dimensional QCD in the large N limit. The model serves as a testing ground to explore methodology of meson mass determination with different techniques and versions of lattice fermions.Go to contribution page
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Mr Matthias Puhr (University of Regensburg)27/07/2016, 12:10We present a method for the numerical calculation of derivatives of functions of general complex matrices which also works for implicit matrix function approximations such as Krylov-Ritz type algorithms. An important use case for the method is the overlap Dirac operator at finite quark chemical potential. The evaluation of the overlap Dirac operator at finite chemical potential calls for...Go to contribution page
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Dr Silvano Simula (INFN - Roma Tre)27/07/2016, 12:10Electromagnetic effects on the leptonic decay rates pi+ -> mu+ nu and K+ -> mu+ nu are evaluated for the first time on the lattice. Following a method recently proposed in Ref. [1] the emission of virtual photons at leading order in the e.m. coupling is evaluated on the lattice with the subtraction of the infrared divergence computed for a point-like meson at finite lattice volume. The...Go to contribution page
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Dr Falk Bruckmann (University of Regensburg)27/07/2016, 12:10We simulated the asymptotically free two-dimensional O(3) model at nonzero chemical potential through dual variables free of the sign problem. The system undergoes a quantum phase transition when mu reaches the particle mass (generated dynamically similar to QCD). The density follows a square root universal for repulsive bosons in one spatial dimension. We have also measured the spin...Go to contribution page
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Mr Senia Valgushev (Regensburg University)27/07/2016, 12:10One of the macroscopic manifestations of the Chiral anomaly in a matter with Dirac fermions is a large negative magnetoresistivity in strong magnetic fields, which is common feature of Weyl- and Dirac semimetals and QCD. However, most of previous studies have been done in the linear response approach in non-interacting theory. We study Magnetoresistivity in a model of Dirac semimetal using...Go to contribution page
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Monika Blanke (Karlsruhe Institute of Technology)28/07/2016, 09:00In this talk I review the implications of recent lattice QCD results on the phenomenology of flavour and CP-violating meson decays. Precise lattice QCD results for hadronic matrix elements, decay constants and form factors play a crucial role in the determination of CKM matrix elements and in the identification of possible new physics contributions to flavour violating observables. I also...Go to contribution page
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ran zhou (Fermi National Accelerator Laboratory)28/07/2016, 09:45Heavy meson decays are used to extract the fundamental parameters in Standard Model such as CKM matrix elements and probe new physics beyond the Standard Model. Lattice QCD provides a non-perturbative method to calculate the matrix elements in these processes. In this talk, I will review recent progress in the study of B and D meson decay constants, semileptonic decay form factors, B and...Go to contribution page
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Dr Amy Nicholson (UC Berkeley)28/07/2016, 10:15While the discovery of non-zero neutrino masses is one of the most important accomplishments by physicists in the past century, it is still unknown how and in what form these masses arise. Lepton number-violating neutrinoless double beta decay is a natural consequence of Majorana neutrinos and many BSM theories, and several experimental efforts are involved in the search for these processes....Go to contribution page
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Agostino Patella (CERN and Plymouth U.)28/07/2016, 11:15When aiming at a percent precision in hadronic quantities calculated by means of lattice simulations, isospin breaking effects become relevant. These are of two kinds: up/down mass splitting and electromagnetic corrections. In order to properly account for the latter, a consistent formulation of electrically-charged states in finite volume is needed. In fact on a periodic torus Gauss' law and...Go to contribution page
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28/07/2016, 12:00
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38. Charge radii and higher electromagnetic moments with lattice QCD in nonuniform background fieldsDr Zohreh Davoudi (MIT)28/07/2016, 14:00Nonuniform background electromagnetic fields, once implemented in lattice QCD calculations of hadronic systems, provide a means to constrain a large class of electromagnetic properties, from higher electromagnetic moments and charge radii to electromagnetic form factors. In this talk, I present the recent theoretical developments in realizing general background fields in periodic hypercubic...Go to contribution page
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Yusuke Namekawa (University of Tsukuba)28/07/2016, 14:00We present our results of charm physics in $N_f=2+1$ lattice QCD. Our calculation is performed on configurations generated with Iwasaki gauge and the six stout smeared $O(a)$-improved Wilson quark actions on a $96^4$ lattice at $\beta=1.82$ ($a^{-1} = 2.3$ GeV) with the spatial extent $L=8.1$ fm. The pion mass is almost physical $m_\pi=145$~MeV. The relativistic heavy quark action is...Go to contribution page
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Prof. Johan Bijnens (Lund University)28/07/2016, 14:00Recent progress in mesonic Chiral Perturbation Theory at finite volume and/or with twisted boundary conditions will be discussed. Topics include the finite volume at two-loop order calculations of masses and decay constants for the pseudoscalar of the normal case for two and three flavours [1], partially quenched three flavour [2] and the case for different patterns of spontaneous...Go to contribution page
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Dr James Osborn (ANL)28/07/2016, 14:00We present a new lattice field theory software framework designed with ease of use, flexibility, efficiency and portability in mind. The framework is written using the Nim programming language which offers many of the features one would find in a high-level scripting language, while in fact being a strongly-typed language with full control over low-level optimizations. This allows us to...Go to contribution page
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Dr Jon-Ivar Skullerud (Maynooth University)28/07/2016, 14:00We present results for correlators and spectral functions of open charm mesons using 2+1 flavours of clover fermions on anisotropic lattices. The D mesons are found to melt close to the deconfinement crossover temperature $T_c$. Our preliminary results suggest a shift in the thermal D meson mass below $T_c$.Go to contribution page
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Prof. Luigi Del Debbio (Edinburgh)28/07/2016, 14:00We study the phenomenology of a specific model of strongly interacting dynamics beyond the Standard Model, and derive the current bounds on the low-energy constants that describe the large-distance behaviour of the model. We deduce from these bounds the required accuracy for lattice simulations to have an impact on searches for new physics beyond the Standard Model.Go to contribution page
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Dr Laurent Lellouch (CNRS & Aix-Marseille U.)28/07/2016, 14:20For the Budapest-Marseille-Wuppertal collaboration We present a lattice study of the u, d and s quark contents of the nucleon, determined using the Feynman-Hellmann theorem. Results are obtained from twenty-nine high-statistics simulations with four flavors of O(a)-improved Wilson quarks, four lattice spacings and a variety of quark masses.Go to contribution page
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Dr Mathias Wagner (NVIDIA)28/07/2016, 14:20Analysis tasks in Lattice QCD often requires solving linear equations for multiple right hand sides for a constant gauge field. Recently deflation methods have become more widely used and proven to be very efficient. They however do require the calculation and storing of eigenvectors which is either not always feasible or too expensive. Here we present results for an implementation of a block...Go to contribution page
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Mr Atsuro Ikeda (Osaka University)28/07/2016, 14:20We study the charm quark diffusion coefficient from nonzero momentum correlator in temporal channel on the quenched lattice. Euclidean correlator in temporal channel with zero momentum is constant as a function of the imaginary time because of the charge conservation. However this quantity with finite momentum is dependent on imaginary time and is more sensitive to the low energy structure of...Go to contribution page
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Mr Marco Garofalo (University of Edinburgh)28/07/2016, 14:20We consider a field theoretical model where a SU(2) doublet fermion, subjected to non-abelian gauge interactions, is also coupled to a complex scalar field doublet via a Yukawa and an irrelevant Wilson-like term. Despite the presence of these two chiral breaking operators in the Lagrangian, an exact symmetry acting on fermions and scalars prevents perturbative mass corrections. In the phase...Go to contribution page
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Dr Elvira Gamiz (University of Granada)28/07/2016, 14:20We present an update of our calculation of the $K_{\ell 3}$ form factor $f_+^{K \pi}(0)$, with added statistics and the inclusion of new ensembles with smaller lattice spacing. In addition, we now also include a study of finite volume effects using a version of staggered ChPT that includes the effects of twisted boundary conditions.We also examine the implications for the unitarity of the CKM...Go to contribution page
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Mr David Tims (Trinity College Dublin)28/07/2016, 14:20Charmed meson spectroscopy with data generated by the Hadron Spectrum Collaboration is presented, using two ensembles with different light sea-quark masses to investigate the effect of the sea quark mass on the spectrum. Initial results from an investigation of the contribution of the disconnected quark-line diagram on the charmonium hyperfine splitting will be presented, including a...Go to contribution page
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Dr Kate Clark (NVIDIA)28/07/2016, 14:40The past decade has witnessed a dramatic acceleration of lattice quantum chromodynamics calculations in nuclear and particle physics. This has been due to both significant progress in accelerating the iterative linear solvers using multi-grid algorithms, and due to the throughput improvements brought by GPUs. Deploying hierarchical algorithms optimally on GPUs is non-trivial owing to the lack...Go to contribution page
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Dr Chia Cheng Chang (LBNL)28/07/2016, 14:40Momentum-space derivatives of matrix elements can be related to their coordinate-space moments through the Fourier transform. We derive these expressions as a function of momentum transfer $Q^2$ for asymptotic in/out states consisting of a single hadron. We calculate corrections to the finite volume moments by studying the spatial dependence of the lattice correlation functions. This method...Go to contribution page
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Dr Tomasz Korzec (Bergische Universität Wuppertal)28/07/2016, 14:40We investigate the influence of dynamical charm quarks on various observables. For observables without explicit charm-quark dependence, decoupling applies and the effects are expected to be small. However, we also study quantities with explicit charm-quark dependence, like the charmonium mass spectrum, where decoupling does not apply. Our study puts an emphasis on careful continuum...Go to contribution page
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Dr Enno E. Scholz (University of Regensburg)28/07/2016, 14:40The leptonic decay-constant ratio $f_K/f_\pi$ is calculated from lattice-QCD simulations using $N_f=2+1$ dynamical fermion flavors in the clover-improved formulation and 2-HEX smearing. The simulations were performed at a range of mass-degenerate light quarks including the physical point and at various lattice couplings and volumes, allowing to quantify all relevant sources of systematic...Go to contribution page
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Mr Maurizio Alberti (University of Wuppertal)28/07/2016, 14:40We report on the progress in the study of a five-dimensional SU(2) Gauge-Higgs Unification model. In the non-perturbative study, the Higgs mechanism is triggered by the spontaneous breaking of a global symmetry. In the same region of the phase diagram, we observe both dimensional reduction and the ratio of Higgs and Z boson masses to take the value known from experiment. We present the...Go to contribution page
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Mr Haitao Shu (CCNU)28/07/2016, 14:40The spectral functions provide us the knowledge to understand the in-medium hadron and transport properties of the QCD medium. For instance, quantities like thermal dilepton production and photon emission rates of QGP can be obtained from the vector spectral functions. Though spectral functions are important, they can not be obtained directly from Euclidean lattice QCD calculations. Analytic...Go to contribution page
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Dr Graham Moir (University of Cambridge)28/07/2016, 15:00We present an extensive study of isospin $1/2$ coupled-channel $D\pi$, $D\eta$ and $D_{s}\bar{K}$ scattering, as well as isospin $3/2$ elastic $D\pi$ scattering, from $N_{f} = 2+1$ lattice QCD. Our use of distillation in combination with variationally optimised interpolating operators allows us to extract statistically precise two-meson spectra, which we use to constrain scattering amplitudes...Go to contribution page
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Dr Yong-Chull Jang (Los Alamos National Laboratory)28/07/2016, 15:00We present the status of the calculation of the nucleon iso-vector axial and vector form factor using the MILC $N_f=2+1+1$ HISQ ensembles with lattice spacings $a=0.12, 0.09$, and $0.06\;\mathrm{fm}$ and three values of light quark masses corresponding to pion masses $310, 220, 130\;\mathrm{MeV}$. Valence quarks are simulated with the clover action. A number of techniques to increase the...Go to contribution page
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Prof. Axel Maas (University of Graz)28/07/2016, 15:00The spectacular success of perturbation theory in electroweak physics hinges on the validity of the Froehlich-Morchio-Strocchi mechanism. This mechanism allows the determination of the spectrum of physical, gauge-invariant states using perturbation theory if a Brout-Englert-Higgs effect is present. For this mechanism to work two preconditions have to be met. One is the structural requirement...Go to contribution page
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Dr Evan Weinberg (Boston University)28/07/2016, 15:00As the push towards the exascale enables increasingly accurate lattice calculations, the inversion of the Dirac matrix becomes a superlinearly growing expense. Adaptive algebraic multigrid (AAMG) methods for all fermion discretizations are essential to address this phenomena of critical slowing down. As a preconditioner, AAMG expedites Dirac matrix inversions with manageable start up costs....Go to contribution page
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Dr Hiroshi Ohno (University of Tsukuba)28/07/2016, 15:00We study charmonium spectral functions at finite temperature by using stochastic reconstruction methods. Our quenched lattice QCD simulations are performed with the standard plaquette gauge and the $O(a)$-improved Wilson fermion actions on 192$^3 \times N_\tau$ lattices with $N_\tau$ = 96--32, which corresponds to temperatures from 0.73$T_c$ to 2.2$T_c$. To reconstruct the charmonium spectral...Go to contribution page
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Dr Roger Horsley (University of Edinburgh)28/07/2016, 15:00The SU(3) flavour symmetry breaking expansion in up, down and strange quark masses is extended from hadron masses to meson decay constants. This allows a determination of the ratio of kaon to pion decay constants in QCD. Furthermore when using partially quenched valence quarks the expansion is such that SU(2) isospin breaking effects can also be determined. It is found that the lowest...Go to contribution page
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Dr Alexander Rothkopf (Institute for Theoretical Physics, Heidelberg University)28/07/2016, 15:20The concept of a screening mass is a powerful tool to simplify the intricate physics of in-medium test charges surrounded by light charge carriers. While it has been successfully used to describe electromagnetic properties, its definition and computation in QCD is plagued by questions of gauge invariance and the presence of non-perturbative contributions from the magnetic sector. Here we...Go to contribution page
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Dr Ken-Ichi Ishikawa (Hiroshima University)28/07/2016, 15:20The most computationally demanding part of Lattice QCD simulations is solving quark propagators. Quark propagators are typically obtained with a linear equation solver utilizing HPC machines. The success of Lattice QCD simulations owes much to the development of numerical algorithms and optimization for the quark solver, and evolution of HPC machines. The CCS QCD Benchmark is a benchmark...Go to contribution page
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Dr Christopher Thomas (University of Cambridge)28/07/2016, 15:20I will discuss a recent lattice QCD investigation of $D$ $K$ scattering relevant for near-threshold charm-strange mesons such as the enigmatic $D_s(2317)$. By employing a range of techniques we extracted precise finite-volume spectra in a number of different channels. These were used to map out the energy dependence of the scattering phase shift and from the singularity structure of the...Go to contribution page
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Nesreen Hasan (Bergische Universitaet Wuppertal)28/07/2016, 15:20We describe a lattice approach for directly computing momentum derivatives of nucleon matrix elements using the Rome method, which we apply to obtain the isovector magnetic moment and Dirac radius. We present preliminary results calculated at the physical pion mass using a 2HEX-smeared Wilson-clover action from the Budapest-Marseille-Wuppertal collaboration. For removing the effects of...Go to contribution page
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Mr Pascal Toerek (University of Graz)28/07/2016, 15:20The description of electroweak physics using perturbation theory is highly successful. Though not obvious, this is due to a subtle field-theoretical effect, the Fröhlich-Morchio-Strocchi mechanism, which links the physical spectrum to that of the elementary particles. This works because of the special structure of the standard model, and it is not a priori clear whether it works for...Go to contribution page
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Kim Maltman (York University)28/07/2016, 15:20We discuss the current status of the determination of V_us based on flavor-breaking finite energy sum rule analyses of non-strange and strange hadronic tau decay data, highlighting the role of lattice input in providing a means of investigating the reliability of the OPE representation for the relevant flavor-breaking polarization combination employed in this analysis, and in quantifying...Go to contribution page
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Dr Jeremy Green (Institut für Kernphysik, Johannes Gutenberg-Universität Mainz)28/07/2016, 15:40A lattice QCD calculation of the light and strange axial form factors $G_A$ and $G_P$ of the nucleon will be reported. Disconnected diagrams were calculated using hierarchical probing, and a clear nonzero signal was obtained. We pay special attention to renormalization, which we determined nonperturbatively, including the mixing between light and strange quarks. This calculation was done on a...Go to contribution page
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Dr Ruizi Li (Indiana University)28/07/2016, 15:40We review our work done to optimize the staggered conjugate gradient(CG) algorithm in the MILC code for use with the Intel Knights Landing (KNL) architecture. KNL is the second generation Intel Xeon Phi processor. It is capable of massive thread parallelism, data parallelism and high on-board memory bandwidth, and is being adopted in supercomputing centers for scientific research. The CG...Go to contribution page
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Mr Antonio Cox (University of Regensburg)28/07/2016, 15:40Early theoretical studies and lattice simulations predicted the charmed-strange mesons $D_{s0}^{*}(2317)$ and $D_{s1}(2460)$ to be broad states lying above the thresholds, $DK$ and $D^{*}K$, respectively. Experiments found narrow states below threshold. We present results of a high statistics $Nf=2$ study with a lattice spacing of approximately $0.071$ fm, taking explicitly into account the...Go to contribution page
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Mr Aman Steinberg (Uni Mainz)28/07/2016, 15:40Thermal screening masses associated to the conserved vector current are calculated both in a weak-coupling and a lattice QCD approach. The inverse of a screening mass can be understood as the length scale over which an external electric field is screened in a QCD medium. The comparison of screening masses in the zero and non-zero Matsubara frequency sectors shows good agreement of the...Go to contribution page
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Dr Hiroshi Ohki (RIKEN BNL Research Center)28/07/2016, 15:40We present a novel approach to determining Vus which employs inclusive strange hadronic tau decay data and hadronic vacuum polarization functions (HVPs) computed on the lattice. The experimental and lattice data are related through dispersion relations which employ a class of weight functions which are products of factors having poles at Euclidean Q^2. Implementing this approach using...Go to contribution page
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Dr Takumi Iritani (Stony Brook University)28/07/2016, 16:30In lattice QCD, both direct method for eigen-energy extraction and HAL QCD method for potential are employed so far to study hadron interactions. The scattering phase shifts, for example, are obtained through the Luscher’s finite volume formula for the former, but they are calculated via the Schroedinger equation with the potential in the infinite volume for the latter. Although both...Go to contribution page
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Prof. Yoshinobu Kuramashi (University of Tsukuba/RIKEN AICS)28/07/2016, 16:30We present preliminary results for nucleon form factors including the axial charge and the Dirac radius in 2+1 flavor QCD at the almost physical pion mass on a $96^4$ lattice with the lattice spacing of 0.084 fm. The configurations are generated with the stout-smeared $O(a)$-improved Wilson quark action and the Iwasaki gauge action at beta=1.82. A large spatial volume of (8.1fm$)^3$ allows us...Go to contribution page
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Dr Gergely Endrodi (University of Frankfurt)28/07/2016, 16:30We study the QCD phase diagram at nonzero isospin chemical potential using 2+1 flavors of staggered fermions with physical quark masses at different lattice spacings and volumes. The talk focuses on the transition to the pion condensation phase at high chemical potentials. This phase is characterized by a proliferation of low modes that slow down the simulation considerably and...Go to contribution page
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Dr Tadeusz Janowski (CP3-Origins)28/07/2016, 16:30SU(2) gauge theories with two quark flavours in the fundamental representation are among the most promising theories of composite dynamics describing the electroweak sector. Three out of five Goldstone bosons in these models become the longitudinal components of the W and Z bosons giving them mass. Like in QCD we expect a spectrum of excitations which appear as resonances in vector boson...Go to contribution page
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Dr Mattia Bruno (Brookhaven Natl. Lab.)28/07/2016, 16:30Perturbation theory plays a significant role in some lattice calculations, in particular in those related to weak processes. Here we discuss the possibility to calculate the Wilson Coefficients of the leading order electro-weak effective Hamiltonian of the Standard model to all order in the strong coupling constant, using lattice simulations.Go to contribution page
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Mr Viljami Leino (University of Helsinki)28/07/2016, 16:50We present preliminary results of the gradient flow running coupling in SU(2) gauge theory with 6 massless fundamental representation fermion flavours. We use the Schrödinger functional boundary conditions, which allows us to also measure the mass anomalous dimension. Our results, using the HEX-smeared Wilson-clover action, are consistent with perturbative running on the weak coupling region...Go to contribution page
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Prof. Sinya Aoki (Yukawa Institute for Theoretical Physics, Kyoto University)28/07/2016, 16:50Since the energy shift of two-baryon system due to the finite volume is negative for the attractive interaction, the Lueshcer's finite volume formula gives the phase shift at negative squared momentum, $k^2 < 0$, for the ground state. The phase shift at $k^2<0$ is not physical in the infinite volume where $k^2$ are all positive except for bound states, but it corresponds to the analytic...Go to contribution page
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Dr Tim Harris (Helmholtz-Institut Mainz)28/07/2016, 16:50We present updated results on the isovector electromagnetic form factors and axial coupling of the nucleon calculated using the CLS ensembles with $N_{\mathrm f}=2+1$ flavours of Wilson fermions. Systematic effects are investigated by covering a range of lattice spacings and pseudoscalar masses. Efficient variance reduction is achieved with the truncated solver method. The strategy to...Go to contribution page
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Dr Christopher Kelly (Columbia University)28/07/2016, 16:50We discuss recent progress by the RBC & UKQCD collaborations in the lattice calculation of the measure of Standard Model direct CP violation, \epsilon', with physical kinematics. We present results with improved systematic errors resulting from the use of step-scaling to reduce the renormalization error, an analysis that also takes into account the one-loop-suppressed mixing with the G_1...Go to contribution page
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Dr Bastian Brandt (University of Frankfurt)28/07/2016, 16:50We investigate the phase diagram of QCD at finite isospin chemical potential using 2+1 flavours of staggered fermions with physical quark masses at different lattice spacings and volumes. In this talk we focus on the region of small isospin chemical potential below the phase boundary to the pion condensation phase and investigate the change of the transition temperature with the chemical...Go to contribution page
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Dr Giannis Koutsou (The Cyprus Institute)28/07/2016, 17:10The nucleon electromagentic and axial form factors are presented using an N$_\textrm{f}$=2 twisted mass fermion ensemble with pion mass of 135 MeV. Dipole masses for the momentum dependence of the form factors are extracted and compared to experiment, as is the nucleon magnetic moment and charge and magnetic radii.Go to contribution page
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Prof. Norman Christ (Columbia University)28/07/2016, 17:10The rare kaon decays K+ -> pi+ nu nu-bar are highly suppressed in the standard model and thus provide an ideal place to search for new physics beyond the standard model. These decays are the principal objective of a new experiment, NA62 at CERN. Another new experiment to search for KL -> pi0 nu nu-bar is now underway at J-PARC. Given the goal of 10% precision by NA62, it is important to...Go to contribution page
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Prof. Benjamin Svetitsky (Tel Aviv University)28/07/2016, 17:10The SU(4) gauge theory with two flavors of Dirac fermions in the sextet representation shares features of a candidate for a composite Higgs model. The analogue of the Higgs multiplet of the Standard Model lives in the Goldstone manifold resulting from spontaneous breaking of the global symmetry SU(4) to SO(4). The Higgs potential arises from interaction with the particles of the Standard...Go to contribution page
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Mr Aleksandr Nikolaev (ITEP)28/07/2016, 17:10In this talk we present our results on the low-temperature scan of the phase diagram of dense two-color QCD with $N_f=2$ quarks. The study is conducted using lattice simulation with rooted staggered quarks. At small chemical potential we observe the hadronic phase, where the theory is in a confining state, chiral symmetry is broken, the baryon density is zero and there is no diquark...Go to contribution page
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Takeshi Yamazaki (Univ. of Tsukuba)28/07/2016, 17:10Recently it was raised a possibility that calculation of the nucleus correlation functions suffers from a significant systematic error due to excited state contributions depending on the choice of the source operator. In order to investigate the operator dependence of the nucleus correlation functions, we have performed a high precision calculation employing the exponential smeared and...Go to contribution page
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Dr Alejandro Vaquero (INFN Sezione Milano Bicocca)28/07/2016, 17:30The latest results from the Twisted-Mass collaboration on disconnected diagrams at the physical value of the pion mass are presented. In particular, we focus on the sigma terms, the axial charges and the momentum fraction. A detailed error analysis for each observable follows, showing the strengths and weaknesses of the one-end trick. Alternatives are discussed.Go to contribution page
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Mr Ziyuan Bai (Columbia)28/07/2016, 17:30We demonstrate the lattice QCD calculation of the long distance contribution to $\epsilon_K$. Due to the singular, short-distance structure of $epsilon_K$, we must perform a short-distance subtraction and introduce a corresponding subtraction term determined from perturbation theory, which we calculate at Next Leading Order (NLO). We perform the calculation on a $24^3 \times 64$ lattice...Go to contribution page
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Mr Takuya Sugiura (RCNP, Osaka University)28/07/2016, 17:30HAL QCD collaboration has mostly considered the lowest order potential of the derivative expansion so far based on the assumption that higher order terms yield minor correction in low energy region. In this study, we aim at investigating the properties of HAL QCD's non-local potentials when the derivative expansion is explicitly performed to higher order. We report the result of our model...Go to contribution page
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168. Towards Partial Compositeness on the Lattice: Baryons with Fermions in Multiple RepresentationsMr William Jay (University of Colorado Boulder)28/07/2016, 17:30We describe our recent lattice study of SU(4) gauge theory with dynamical Wilson-clover fermions in the fundamental and sextet representations. In this theory, a unique type of baryon consists of quarks in both representations. The spectrum of these "chimera baryons" turns out to have enlightening interpretations in terms of large-N expansion and the non-relativistic quark model. We also...Go to contribution page
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Mr Lukas Holicki (Justus-Liebig-University Giessen)28/07/2016, 17:30Lattice simulations of two-colour QCD can be performed at finite density without sign problem and by now have a long history already. The physics of the bosonic diquark baryons is believed to be fairly well understood and qualitatively resembles QCD at finite isospin density with pion condensation. There is good guidance from effective field theory predictions and model studies of the BEC-BCS...Go to contribution page
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Dr Jarno Rantaharju (CP3-Origins)28/07/2016, 17:50Four fermion interactions appear in many models of Beyond Standard Model physics. In composite Higgs models Standard Model fermion masses can be generated by four fermion terms. They are also expected to modify the dynamics of the new strongly interacting sector. In particular in technicolour models it has been suggested that they can be used to break infrared conformality and produce a...Go to contribution page
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Mr Bardiya Bahrampour (Justus-Liebig University Giessen)28/07/2016, 17:50The strong coupling expansion of the lattice gauge action leads to a Polyakov loop model that effectively describes the gluodynamic at low temperatures and together with the hopping expansion of the fermion determinant allows for insights into the QCD phase diagram at finite density and low temperatures, although the accessible pion masses are rather large. At high temperatures the strong...Go to contribution page
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Dr Rajan Gupta (Los Alamos National Laboratory)28/07/2016, 17:50High precision estimates of the iso-vector nucleon charges g_A, g_S and g_T, electric, magnetic and axial form factors measured on four ensembles of 2+1 flavor clover fermions will be presented and compared with those from clover-on-HISQ calculations. An analysis of systematic uncertainties due the lattice volume, lattice spacing, quark mass and renormalization will also be presented for both...Go to contribution page
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Mr Andrew Lawson (University of Southampton)28/07/2016, 17:50The rare decays of a kaon into a pion and a lepton/antilepton pair proceed via a flavour changing neutral current and therefore first arise in the Standard Model only as a second order electroweak interaction. This natural suppression makes these decays sensitive to the effects of potential New Physics. However the rare decay channels K+ -> pi+ l+ l- are dominated by contributions from...Go to contribution page
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Mr Takaya for HAL QCD Collaboration Miyamoto (Yukawa Institute for Theoretical Physics, Kyoto University)28/07/2016, 17:50We investigate the 2-baryon system with the isospin 1/2 including one charm quark, namely, $\Lambda_c N$ and $\Sigma_c N$. Although this system is similar to the $\Lambda N$ and $\Sigma N$ system, the interaction of this charmed 2-baryon system above $\Sigma_c N$ threshold might be quite different from its hyperon counter part, due to the smaller mass splitting between $\Sigma_c$ and...Go to contribution page
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Daisuke KAWAI (Kyoto University)28/07/2016, 18:10The first principle calculation of hadron-hadron interaction is an important step toward the understanding of nuclear physics from QCD. The HAL QCD method is largely contributing to this purpose by making it possible to calculate nuclear potentials in lattice QCD. We now try to extend the HAL QCD method to systems such as $\pi-\pi$ and $\pi-N$, where pair creation and annihilation of quarks...Go to contribution page
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Dr Jeffrey Greensite (San Francisco State University)28/07/2016, 18:10The relative weights method is applied to extract the effective Polyakov line action corresponding to SU(3) gauge theory with dynamical staggered fermions, and this theory is solved, at finite chemical potential and a few sample temperatures, quark masses, and couplings, by a mean field technique. The effective Polyakov line action is highly non-local, and in at least one case we encounter...Go to contribution page
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Mr Martin Hansen (CP3-Origins, University of Southern Denmark)28/07/2016, 18:10We present new results from our ongoing study of the SU(3) "sextet model" with two flavors in the 2-index symmetric representation of the gauge group. The simulations use unimproved Wilson fermions and to address the issue of whether or not the model is inside the conformal window, we measure the meson and baryon spectrum. To better understand the overall behavior of the lattice model we map...Go to contribution page
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Aaron Meyer (University of Chicago/Fermilab)28/07/2016, 18:10The nucleon axial form factor is a dominant contribution to errors in neutrino oscillation studies. Lattice calculations have the potential to make an impact on controlling theory errors by disentangling the effects of nuclear corrections and nucleon form factors. In this talk, I will present preliminary results on a blinded calculation of $g_A$ and the axial form factor using HISQ staggered...Go to contribution page
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Prof. Heng-Tong Ding (Central China Normal University)29/07/2016, 09:00I will review some recent selected results from Lattice QCD computations at nonzero temperature and density.Go to contribution page
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Prof. Seyong Kim (Sejong University)29/07/2016, 09:45Heavy quark system offers opportunities and challenges for theoretical (and experimental) investigations on the properties of Quark-Gluon Plasma (QGP). Here, recent progresses in the studies of heavy quarks and quarkonia in QGP are discussed. In particular, the results from the calculation of heavy quark kinetic/chemical equilibration in QGP and those from the studies of quarkonia behaviors at...Go to contribution page
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Prof. Kurt Langfeld (Plymouth University)29/07/2016, 10:15Although Monte Carlo calculations using Importance Sampling have matured into the most widely employed method for determining first principle results in QCD, they spectacularly fail for theories with a sign problem or for which certain rare configurations play an important role. Non-Markovian Random walks, based upon iterative refinements of the density-of-states, overcome such overlap...Go to contribution page
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Prof. Aleksi Kurkela (CERN and Univ. Stavanger)29/07/2016, 11:15Phenomenology of Heavy Ions and LQCDGo to contribution page
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Prof. Hiroshi Suzuki (Kyushu University)29/07/2016, 12:00It is conceivable that the construction of the energy-momentum tensor in lattice field theory enlarges our ability in lattice field theory and also deepens our understanding on the energy-momentum tensor in the non-pertubative level. In this talk, I will review recent developments in this enterprise.Go to contribution page
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Mr Tobias Rindlisbacher (ETH Zürich)29/07/2016, 14:00The CP(N-1) model in 2D is an interesting toy model for 4D QCD as it possesses confinement, asymptotic freedom and a non-trivial vacuum structure. Due to the lower dimensionality and the absence of fermions, the computational cost for simulating 2D CP(N-1) on the lattice is much lower than the one for simulating 4D QCD. However to our knowledge, no efficient algorithm for simulating the...Go to contribution page
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Prof. Guido Martinelli (Universita' di Roma "La Sapienza" and Cern)29/07/2016, 14:00We investigate the topological properties of $N_f = 2 + 1$ QCD with physical quark masses, both at zero and finite temperature. At zero temperature both finite size and finite cut-off effects have been studied by comparing the continuum extrapolated results for the topological susceptibility $\chi$ with the predictions from chiral perturbation theory. At finite temperature, we explore...Go to contribution page
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Doi Takumi (RIKEN)29/07/2016, 14:00The lattice QCD determination of baryon interactions corresponds to connecting a missing link between particle physics and nuclear and astrophysics. While previous studies are limited to the calculations with unphysically heavy quark masses, we are performing the first calculation employing the (almost) physical quark masses (m(pi) = 146 MeV) on a huge lattice volume of (8fm)^4, where the...Go to contribution page
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Mr Justus Tobias Tsang (University of Southampton)29/07/2016, 14:00This talk will provide an overview of RBC/UKQCD's charm project on their 2+1 flavour physical point ensembles using Domain Wall Fermions for the light as well as for the charm quarks. I will discuss the analysis strategy and present the latest results for the $D$ and $D_s$ decay constants. I will also outline the wider charm-related physics program of RBC/UKQCD.Go to contribution page
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Dr Benoît Blossier (CNRS/LPT Orsay)29/07/2016, 14:00In many lattice simulations with dynamical quarks, radial or orbital excitations of hadrons lie near multihadron thresholds: it makes the extraction of excited states properties more challenging and cqn introduce some systematics difficult to estimate without an explicit computation of correlators using interpolating fields strongly coupled to multihadronic states. In a recent study...Go to contribution page
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Dr Claudio Bonati (Università di Pisa)29/07/2016, 14:00Studies of the large N behaviour of the topological properties of gauge theories typically focused on the large N scaling of the topological susceptibility. A much more difficult task is the study of the behaviour of higher cumulants of the topological charge in the large N limit, which up to now remained elusive. We will present first results confirming the expected large N scaling of the...Go to contribution page
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Dr Takashi Kaneko (KEK)29/07/2016, 14:20We report on our study of $D$ meson semileptonic decays in 2+1 flavor lattice QCD. Gauge ensembles are generated at the lattice cutoffs around 2.5 GeV and above and at pion masses as low as 300 MeV. We employ the Moebius domain-wall action for both light and charm quarks. We report our preliminary results for the vector and scalar form factors.Go to contribution page
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Prof. Noriyoshi Ishii (Research Center for Nuclear Physics (RCNP), Osaka University)29/07/2016, 14:20Nucleon-Nucleon interaction plays an essential role in nuclear physics. In the same way, hyperon-hyperon interactions should play an important role in hyper nuclear physics. However, unlike the nucleons which are quite stable, hyperons decay quickly so that the direct scattering experiments are difficult. As a result, phenomenological determination of hyperon potentials...Go to contribution page
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Dr Maxwell Hansen (University of Mainz)29/07/2016, 14:20Excited-state contamination is one of the dominant uncertainties in lattice calculations of nucleon charges and form factors. To estimate this uncertainty one needs the finite-volume energy spectrum as well as the finite-volume matrix elements that determine the coefficients of excited state exponentials. In this work we use experimental data, supplemented by chiral perturbation theory (ChPT),...Go to contribution page
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Mr Davide De Boni (Swansea University)29/07/2016, 14:20At zero temperature nucleons and their parity partners have non-degenerate masses due to spontaneous breaking of chiral symmetry. However, chiral symmetry is expected to be restored at sufficiently high temperature, in particular when going from the hadronic to the quark-gluon plasma (QGP) phase, implying that the parity partners should become degenerate. We study the nucleon (spin 1/2)...Go to contribution page
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Dr Wynne Evans (University of Bern)29/07/2016, 14:20CP(N-1) quantum field theories in (1+1)-d share important features with (3+1)-d QCD, such as asymptotic freedom, a dynamically generated mass gap and topological sectors. In the low energy limit the (2+1)-d SU(3) spin system undergoes spontaneous symmetry breaking and hence dimensional reduction to the (1+1)-d CP(2) model. By performing Monte Carlo simulations of (2+1)-d SU(3) spin systems at...Go to contribution page
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Miguel Francisco Garcia Vera (NIC, DESY & Humboldt Universitat zu Berlin)29/07/2016, 14:20We present a precise computation of the topological susceptibility $\chi$ of SU($N$) Yang–Mills theory in the large-$N$ limit. The computation is done on the lattice, using high-statistics Monte Carlo simulations of the SU($N$) Yang-Mills theories, with $N=3, 4, 5, 6$ and three different lattice spacings. Two major improvements allowed us to go to finer lattice spacing and larger $N$ compared...Go to contribution page
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Dr Kenji Sasaki (Kyoto University)29/07/2016, 14:40Baryon interactions are crucial to study a bound and/or resonance state in multi-baryon systems. In spite of their importance, phenomenological baryon potentials have large uncertainties because of the lack of experimental scattering data. In recent studies, the HAL QCD method allow us to extract baryon interactions from the Nambu-Bethe-Salpeter wave functions without using experimental...Go to contribution page
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Mr Junpei Kakazu (University of Tsukuba)29/07/2016, 14:40We present preliminary result of the electromagnetic form factor of the pion at $m_\pi=0.145$ GeV on the large volume corresponding to $L = 8.1$ fm using stout-smearing Wilson clover quark action and Iwasaki gauge action at $a^{-1}=2.333$ GeV. The mean square charge radius is estimated from the results at small space-like momentum transfer with the NLO formula in SU(2) chiral perturbation...Go to contribution page
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Giorgio Salerno (Università di Roma Tre)29/07/2016, 14:40We present lattice results of the form factors relevant for semileptonic $D\to\pi \ell \nu$ decays, using the gauge ensembles produced by the European Twisted Mass Collaboration with Nf=2+1+1 flavors of dynamical quarks, at three values of the lattice spacing and pion masses as low as 210 MeV. We have computed the matrix elements of both the vector and scalar weak currents for several...Go to contribution page
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Dr Jong-Wan Lee (Swansea University)29/07/2016, 14:40Recently the two-color gauge theory with two flavors of fundamental fermions has received considerable attention in BSM model building, as it provides a minimal template for a composite Higgs theory that includes dark matter candidates. In this work, we consider the two-color model with two flavors of Wilson fermions at non-zero temperature. For a more reliable investigation of meson...Go to contribution page
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Mr Vadacchino Davide (Universita' degli Studi di Torino - INFN Torino)29/07/2016, 14:40The dual formulation of the compact U(1) lattice gauge theory in three spacetime dimensions allows to finely study the squared width and the profile of the confining fluxtube on a wide range of physical interquark distances. The results obtained in Montecarlo simulations are compared with the predictions of the effective bosonic-string model and with the dual superconductor model. While the...Go to contribution page
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Dr Bjoern Wellegehausen (ITP University Giessen)29/07/2016, 14:40Theoretical knowlegde about the nonperturbative aspects of the phase diagram of QCD is of utmost importance for the design of future collider experiments or the understanding of cold and dense neutron stars. Since lattice QCD suffers from a severe sign problem at finite density, QCD-like theories are useful to understand the phase diagram of baryonic matter at finite density. Most...Go to contribution page
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Dr Matteo Giordano (Eötvös University, Budapest)29/07/2016, 15:00I discuss chiral symmetry restoration and eigenmode localisation in finite-temperature QCD by looking at the lattice Dirac operator as a random Hamiltonian. I will argue that the features of QCD relevant to both phenomena are the presence of order in the Polyakov line configuration, and the correlations that this induces between spatial links across time slices. This ties the fate of...Go to contribution page
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Mr Csaba Torok (Eotvos University, Budapest)29/07/2016, 15:00We study the 1+1 dimensional nonlinear O(3) model at finite chemical potential using the complex Langevin algorithm and the worm algorithm. In the latter the sign problem is totally eliminated. We determine the range of parameters, where complex Langevin produces correct results and study whether taking the continuum limit allows the exploration of the full phase diagram of the model.Go to contribution page
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Dr Andrea Rucci (University of Pisa and INFN Pisa)29/07/2016, 15:00I will discuss some recent results obtained in the study of the strong quark-antiquark interaction in the presence of intense external magnetic fields. At zero temperature the external field induces anisotropies in the static quark potential, that affect both the spectrum and the decays of the heavy mesons. In the quark-gluon plasma phase the screening masses do not show significant...Go to contribution page
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Dr Hidekatsu Nemura (Center for Computational Sciences, University of Tsukuba)29/07/2016, 15:00We present our recent study on baryon-baryon (BB) interactions from lattice QCD with almost physical quark masses corresponding to $(m_\pi,m_K)\approx(146,525)$ MeV and large volume $(La)^4=(96a)^4\approx$ (8.2 fm)$^4$. In order to make better use of large scale computer resources, a large number of BB interactions from NN to $\Xi\Xi$ are calculated simultaneously. In this...Go to contribution page
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Aurora Melis (RomaTre University)29/07/2016, 15:00We present the results of a Lattice QCD determination of the heavy-light vector mesons masses and decay constants. The vector decay constants are relevant hadronic parameters that, for instance, can provide phenomenologically good descriptions of non-leptonic decay rates within the factorization approximation. Our calculation is based on the gauge configurations generated by the European...Go to contribution page
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Mr Bartosz Kostrzewa (HISKP (Theory) - Universitaet Bonn)29/07/2016, 15:00We present an investigation of pion structure based on ETMC $N_f=2$ and $N_f=2+1+1$ twisted mass configurations at maximal twist. We compute the first two moments of the quark momentum fraction of the pion and the electromagnetic form factor. For the latter, momentum is injected using twisted boundary conditions and $F_\pi(Q^2)$ is calculated at the physical pion mass. We find that our...Go to contribution page
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Dr Guido Cossu (Higgs Centre for Theoretical Physics, School of Physics and Astronomy, University of Edinburgh)29/07/2016, 15:20We investigate the properties of the background gauge field configurations that act as disorder for the Anderson localization mechanism in the Dirac spectrum of QCD at high temperatures. We compute the eigenmodes of the M\"obius domain-wall fermion operator on configurations generated for the $SU(3)$ gauge theory with two flavors of fermions, in the temperature range $[0.9,1.9]T_c$. We...Go to contribution page
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Dr Brendan Fahy (KEK)29/07/2016, 15:20We explore the properties of heavy-light psuedoscalar mesons above the charm mass sing Mobius domain-wall fermions on fine lattices at a~0.080, 0.055, and 0.044 fm. We examine masses and decay constants using a series of heavy quark masses up to 3 times the charm quark. We attempt to analyze the cutoff effects for heavy quarks above the charm and account for the low order effects using...Go to contribution page
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Prof. Steven Gottlieb (Indiana University)29/07/2016, 15:20We present a calculation of the form factors of the $D\to K l \nu$ and $D\to\pi l \nu$ semileptonic decays at zero momentum transfer, ultimately for the purpose of determining the CKM matrix elements $|{V_{cs}}|$ and $|{V_{cd}}|$. This work uses MILC $N_f=2+1+1$ configurations with the HISQ action for both sea quarks and valence quarks, including several physical mass ensembles and lattice...Go to contribution page
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Meinulf Goeckeler (University of Regensburg)29/07/2016, 15:20We present preliminary results of the RQCD collaboration for the lowest moments of the distribution amplitudes of the rho meson obtained from simulations with 2 degenerate flavours of clover fermions. The quark masses are chosen such that we have rho masses below the decay threshold as well as above threshold. Treating the rho as a stable particle, we find results for small quark masses...Go to contribution page
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Mr Jacob Wellnhofer (Universität Regensburg)29/07/2016, 15:20We study scalar QCD at nonzero density in the strong coupling limit. It has a sign problem which looks structurally similar to the one in QCD. After introducing dual variables by integrating out the SU(3) gauge links we find that we need at least 3 flavors for a nontrivial dependence on the chemical potential. In this dual representation there is no sign problem remaining. The dual...Go to contribution page
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Dr Michael Teper (University of Oxford)29/07/2016, 15:20We summarise the most striking features of the spectra of closed confining flux tubes, for the flux in the fundamental and some other representations. We compare to recent theoretical predictions. In $D=2+1$ we present results for the continuum string tensions for theories ranging from SU(2) to SU(16) and we determine the leading correction to the N-dependence of k-strings.Go to contribution page
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Prof. Nilmani Mathur (Tata Institute of Fundamental Research)29/07/2016, 15:40We present ground state spectra of mesons containing a charm and a bottom quark. For the charm quark we use overlap valence quarks while a non-relativistic formulation is utilized for the bottom quark on a background of 2+1+1 flavor HISQ gauge configurations generated by the MILC collaboration. We also study the ratio of leptonic decay constants, $f_{B_c^*}/f_{B_c}$. Results are obtained...Go to contribution page
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Dr Andreas Kronfeld (Fermilab)29/07/2016, 15:40We present results for neutral $D$-meson mixing in 2+1-flavor lattice QCD. We compute the matrix elements for all five operators that contribute to $D$ mixing at short distances, including those that only arise beyond the Standard Model. We present a detailed error breakdown for all sources of statistical and systematic uncertainty and the corresponding set of correlations among the matrix...Go to contribution page
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Mr Philipp Scior (TU Darmstadt)29/07/2016, 15:40We study the heavy quark limit of QCD-like theories by using a three-dimensional Polyakov theory. This theory can be derived from the full QCD-like theory by a combined strong coupling and hopping expansion. In particular we investigate the cold and dense regime of the phase diagram where we expect to find the Silverblaze property realized as Bose-Einstein-condensation of diquarks or a fist...Go to contribution page
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Mr Finn M. Stokes (University of Adelaide)29/07/2016, 15:40Variational analysis techniques in lattice QCD are powerful tools that give access to the full spectrum of QCD. At zero momentum, these techniques are well established and can cleanly isolate energy eigenstates of either positive or negative parity. In order to compute the form factors of a single energy eigenstate, we must perform a variational analysis at nonzero momentum. When we do this...Go to contribution page
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Dr Leonardo Cosmai (INFN)29/07/2016, 15:40We investigate the transverse profile of the chromoelectric field generated by a quark-antiquark pair in the vacuum of (2+1) flavor QCD. Monte Carlo simulations are performed adopting the HISQ/tree action discretization, as implemented in the publicly available MILC code, suitably modified to measure the chromoelectric field. We work on the line of constant physics, with physical...Go to contribution page
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Dr Daisuke Kadoh (Keio Univ.)29/07/2016, 15:40We present a precision test of the gauge gravity duality in two-dimensional N=(8,8) SYM. We employ the Sugino lattice action to perform lattice simulations of N=(8,8) SYM at finite temperature. We show the evidence of validity of the duality conjecture by comparing lattice results with analytical predictions of the corresponding gravitational theory.Go to contribution page
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Dr Waseem Kamleh (University of Adelaide)29/07/2016, 16:30We reveal a fundamental connection between centre vortices and several key features associated with dynamical chiral symmetry breaking and quark confinement. Calculations are performed in pure $\mathrm{SU}(3)$ gauge theory using the chiral overlap fermion action. Starting from the original gauge field, a vortex identification procedure yields vortex-removed and vortex-only backgrounds....Go to contribution page
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Claude Bernard (Washington University), Javad Komijani (Technische Universit\"at M\"unchen)29/07/2016, 16:30We present high-precision results for the decay constants $f_B$ and $f_{B_s}$ from simulations with HISQ heavy and light valence and sea quarks. Calculations are carried out with several heavy valence-quark masses on ensembles with 2+1+1 flavors of HISQ sea quarks. We generate data at five lattice spacings with three light sea quark mass ratios, including an approximately physical...Go to contribution page
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Phiala Shanahan (Massachusetts Institute of Technology)29/07/2016, 16:30We present the first lattice QCD study of the double-helicity-flip leading-twist gluonic structure function ∆(x,Q2). In particular, we calculate its leading moment in a φ meson and find a robust signal. This quantity is particularly interesting since, unlike the unpolarised and helicity gluon distributions, the double-helicity-flip density is a clean measure of gluonic degrees of freedom as it...Go to contribution page
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Mr Wolfgang Unger (Bielefeld University)29/07/2016, 16:30Lattice QCD in the strong coupling limit with staggered quarks gives rise to a dual representation. Here, the sign problem is mild enough to study the phase diagram at finite density. In the strong coupling limit, the first order nuclear and chiral transition at low temperatures coincide due to Pauli saturation. Away from the strong coupling limit, incorporating higher order gauge...Go to contribution page
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Dr Michele Pepe (INFN - Sez. Milano Bicocca - Italy)29/07/2016, 16:30The thermodynamic properties of the $SU(3)$ Yang-Mills theory are investigated from the confining phase up to 250 $T_c$. Results for the temperature dependence of the entropy density, energy density and pressure are presented with an accuracy of about 0.5%. The framework of shifted boundary conditions is considered where the entropy density is related to the expectation value of the...Go to contribution page
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Wolfgang Soeldner (Regensburg University)29/07/2016, 16:30We present results obtained by RQCD on various observables, obtained from simulations of $N_f=2+1$ flavours of non-perturbatively order-$a$ improved Wilson fermions, employing open boundary conditions in time, that were created within the CLS (Coordinated Lattice Simulations) effort. Configurations at five different values of the lattice spacing, ranging from 0.086 fm down to below 0.04 fm...Go to contribution page
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Dr Nigel David Cundy (Seoul National University)29/07/2016, 16:50In earlier work, we used a gauge independent Abelian Decomposition to show that Abelian degrees of freedom where wholly responsible for the static quark postential. The Abelian decomposition contains a Maxwell part and Topological part, whose contribution to the string tension can be analysed theoretically and numerically, and arises because of the existence of a certain type of monopole. If...Go to contribution page
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Dr Shinji Ejiri (Niigata University)29/07/2016, 16:50We calculate the energy gap (latent heat) and pressure gap between the hot and cold phases of the SU(3) gauge theory at the first order deconfining phase transition point. We perform simulations around the phase transition point with the lattice size in the temporal direction Nt=6, 8 and 12 and extrapolate the results to the continuum limit. The energy density and pressure are...Go to contribution page
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Prof. Stefan Meinel (University of Arizona / RIKEN BNL Research Center)29/07/2016, 16:50Experimental results for mesonic $b \to s \mu^+ \mu^-$ decays show a pattern of deviations from Standard-Model predictions. These deviations could be due to new fundamental physics or due to an insufficient understanding of hadronic effects. Complementary information on the $b \to s \mu^+ \mu^-$ transition can be obtained from $\Lambda_b$ decays. This was recently done using the process...Go to contribution page
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Dr Elena Luschevskaya (State Scientific Center of Russian Federation - Institute of Theoretical and Experimental Physics)29/07/2016, 16:50We explore the ground state energy of pseudoscalar charged and neutral mesons as a function of external magnetic field in SU(3) lattice gauge theory. We calculate the dipole magnetic polarizabilities and hyperpolarizabilities of charged and neutral pseudoscalar pi and K mesons. It was found that the magnetic polarizability of charged pion agrees with the experimental prediction of COMPASS...Go to contribution page
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Dr Jangho KIM (Fakultät für Physik, Universität Bielefeld)29/07/2016, 16:50Strong coupling lattice QCD in the dual representation allows to study the full mu-T phase diagram, due to the mildness of the sign problem. This has been done in the chiral limit. Here we extend the phase diagram to finite quark masses. We present our results on the quark mass dependence of the QCD critical end point obtained by Monte Carlo via the worm algorithm. We compare our simulations...Go to contribution page
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Prof. Gunnar Bali (University of Regensburg)29/07/2016, 16:50We present results obtained by RQCD on various observables, obtained from simulations of $N_f=2+1$ flavours of non-perturbatively order-$a$ improved Wilson fermions, employing open boundary conditions in time, that were created within the CLS (Coordinated Lattice Simulations) effort. Configurations at five different values of the lattice spacing, ranging from 0.086 fm down to below 0.04 fm...Go to contribution page
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Ms Olga Soloveva (Institute for Theoretical and Experimental Physics & National Research Nuclear University MEPhI (Moscow Engine ering Physics Institute))29/07/2016, 17:10We have explored ground state energies of the light vector mesons on the base of the $SU(3)$ lattice gauge theory. This study was performed without dynamical quarks. We have observed the energies spliting depending on the value of the spin projections on an external magnetic field. The ground state energy of neutral mesons with the $s_z = 0$ diminishes with the increase of the field, while the...Go to contribution page
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Akihiro Shibata (Computing Research Center, KEK)29/07/2016, 17:10Go to contribution page
The dual superconductivity is a promising mechanism for quark confinement. We have presented a new formulation of the Yang-Mills theory on the lattice, that enables us to change the original non-Abelian gauge field into the new field variables such that one of them called the restricted field gives the dominant contribution to quark confinement in the gauge-independent way. We...
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Robert Mawhinney (Columbia University)29/07/2016, 17:10The RBC and UKQCD Collaborations have used 2+1 flavor Domain Wall Fermion ensembles, generated with the Iwasaki gauge action plus the Dislocation Suppressing Determinant Ratio (DSDR), for a variety of calculations, including our ongoing G-parity calculation of $K \to \pi \pi$ matrix elements. These calculations have been done with 1/a = 1.35 GeV. With the HotQCD Collaboration, zero and...Go to contribution page
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Mr Edwin Lizarazo (University of Southampton)29/07/2016, 17:10We present an update on our calculation of short distance contributions to semi-leptonic form factors for rare $B$ decays. Results for $B_s \to \phi \ell^+\ell^-$ at three lattice spacings of $a^-1 = 1.78$, 2.38, and 2.76 GeV are shown. Our calculations are based on RBC-UKQCD's $N_f = 2+1$ domain-wall fermion and Iwasaki gauge field ensembles. The heavy $b$-quarks are simulated using the...Go to contribution page
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Dr Yusuke Taniguchi (University of Tsukuba)29/07/2016, 17:10Topological susceptibility brings important information of the QCD vacuum and contributes to a production of the axion. The temperature dependence of the topological susceptibility plays a crucial role in its production rate in the early universe. It is a test whether the axion can be an appropriate candidate of the dark matter. In this talk we report our recent study on the topological...Go to contribution page
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Helvio Vairinhos (ETH Zurich)29/07/2016, 17:10In the strong coupling limit, n-point functions in lattice QCD with staggered fermions can be rewritten exactly as traces over constrained configurations of monomers, dimers, and baryon loops covering the spacetime lattice. Worm algorithms provide efficient global sampling methods over such ensembles, and are particularly efficient in the chiral limit. We study the thermodynamics of...Go to contribution page
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Dr Chris Bouchard (William & Mary)29/07/2016, 17:30We report on our ongoing calculation of the $B\to\pi$ semileptonic decay form factors using NRQCD/HISQ valence quarks with MILC's $N_f=2+1$ asqtad ensembles. The use of HISQ light quarks allows simulation at large pion momenta, corresponding to $q^2\approx 0$, with controlled $(ap)^2$ errors. We perform a simultaneous chiral, continuum, and kinematic extrapolation using the Hard Pion ChPT...Go to contribution page
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Ms Carla Marchis (University of Graz)29/07/2016, 17:30We present a dual approach for SU(2) lattice gauge theory, i.e., an exact mapping of the partition sum to new, so-called dual variables. The dual representation is constructed by decomposing the Wilson gauge action into “abelian color cycles” (ACC), which are loops in color space around plaquettes. The ACCs are complex numbers and as such commute, such that a dual representation can be...Go to contribution page
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Mr Christian Zimmermann (University of Regensburg)29/07/2016, 17:30The effects of double hard interactions are no longer negligible at energy scales reached at the LHC. Double parton scattering (DPS) processes are often described by taking the product of two single parton scattering processes assuming that interference effects are very small. We calculate four point functions (4pt-functions), which appear in the the DPS cross section, employing lattice...Go to contribution page
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Valentina Forini (Humboldt University Berlin)29/07/2016, 17:30String sigma-models relevant in AdS/CFT are highly non-trivial two-dimensional field theories whose perturbative analysis is being crucially used to verify various conjectures, among which their integrability. I will discuss significant progress on how to address the extraction of information at finite values of the string effective tension via the use of lattice-based methods.Go to contribution page
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28. The Dark Side of the Propagators: analytical approach to QCD in the infrared of Minkowski space.Prof. Fabio SIRINGO (Dipartimento di Fisica e Astronomia, Università di Catania)29/07/2016, 17:30Since most of the non-perturbative approaches to QCD rely on numerical calculations in the *Euclidean* space, many important dynamical information cannot be easily extracted because of the ill-defined problem of analytic continuation for a limited set of data points. On the other hand, by a shift of the expansion point, a perturbative approach has been developed[1,2] that has the nice feature...Go to contribution page
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Dr Saumen Datta (Tata Institute of Fundamental Research)29/07/2016, 17:30We use the Wilson flow to study the deconfinement transition. We construct renormalized observables sensitive to the deconfinement transition. In particular, behavior of renormalized operators associated with the Polyakov loop are investigated for both quenched and two-flavor QCD. We also investigate the behavior of various thermodynamic quantities across the transition.Go to contribution page
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Dr Luka Leskovec (University of Arizona)29/07/2016, 17:50Lattice QCD calculations of radiative transitions between hadrons have in the past been limited to processes of hadrons stable under the strong interaction. Recently developed methods for $1 \to 2$ transition matrix elements in a finite volume now enable the determination of radiative decay rates of strongly unstable particles. Our lattice QCD study focuses on the process $\pi \pi \to \pi...Go to contribution page
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Dr Debasish Banerjee (NIC, DESY)29/07/2016, 17:50We report on a recent computation of the form factors in semi-leptonic decays of the $B_s$ using Heavy Quark Effective Theory (HQET) formalism applied on the lattice. The connection of the form factors with the 2-point and 3-point correlators on the lattice is explained, and the subsequent non-perturbative renormalization of HQET and it's matching to $N_f=2$ QCD is outlined. The results of the...Go to contribution page
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Dr Ferenc Pittler (Eötvös University)29/07/2016, 17:50The spectrum of the two-dimensional continuum Dirac operator in the presence of a uniform background magnetic field consists of Landau levels, which are degenerate and separated by gaps. On the lattice the Landau levels are spread out by discretization artefacts, but a remnant of their structure is clearly visible (Hofstadter butterfly). If one switches on a non-Abelian interaction, the...Go to contribution page
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Dr Evan Berkowitz (LLNL)29/07/2016, 17:50Gauge/gravity duality is the conjecture that string theories have dual descriptions as gauge theories. Weakly-coupled gravity is dual to strongly-coupled gauge theories, ideal for lattice calculations. I will show precision lattice calculations that confirm large-N continuum D0-brane quantum mechanics correctly reproduces the leading-order supergravity prediction for a black hole's internal...Go to contribution page
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Dr Victor Braguta (ITEP)29/07/2016, 17:50This report is devoted to the study of temperature dependence of shear viscosity in SU(3)-gluodynamics. To calculate shear viscosity we measured the correlation function of the energy-momentum tensor T_{12}T_{12} for a set of temperatures in the region T/T_c \in (0.9, 1.5). The measurements were carried out using multilevel algorithm which considerably improves the accuracy of the...Go to contribution page
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Dr Andre Sternbeck (University of Jena)29/07/2016, 17:50We report on new results for the triple-gluon and the quark-gluon vertex in Landau gauge. Our results are based on two-flavor and quenched lattice QCD calculations for different quark masses, lattice spacings and volumes. We will focus on the momentum dependence of the different tensor structures.Go to contribution page
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Dr Mateusz Koren (NIC, DESY Zeuthen)29/07/2016, 18:10The extraction of bare ground-state matrix elements for $B_s \to K\ell\nu$ decay at 2% precision poses a significant numerical challenge. Especially the B-sector, treated in HQET, is problematic due to large contamination by excited states combined with the signal-to-noise problem. The numerical setup that we use provides access to all time separations for both the two-point and three-point...Go to contribution page
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Dr Paulo Silva (Center for Physics, University of Coimbra)29/07/2016, 18:10In lattice QCD the computation of one-particle irreducible (1PI) Green's functions with a large number (> 2) of legs is a challenging task. Besides tuning the lattice spacing and volume to reduce finite size effects, the problems associated with the estimation of higher order moments via Monte Carlo methods and the extraction of 1PI from complete Green's functions are limitations of the...Go to contribution page
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Dr Antoine Gerardin (Institute for Nuclear Physics, University of Mainz)29/07/2016, 18:10We report on the lattice QCD calculation of the $\pi^0 \to \gamma^\ast \gamma^\ast$ form factor using two flavors of O(a)-improved Wilson fermions with photon virtualities in the range $Q^2 \in [0-1.5]$~GeV$^2$. Different lattice spacings and pion masses are used to extrapolate our result to the physical point. First, we check that our results, once extrapolated to the chiral and continuum...Go to contribution page
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Ms Marietta Magdolna Homor (Eotvos Lorand University)29/07/2016, 18:10Motivated by the hadronization properties of heavy-ion and p-p collisions, we study the thermalisation properties of field theories. First of all, we present our recent observations regarding the local energy-density and momentum distributions in the classical Phi^4 theory. As this theory exhibits interesting features regarding these questions, we continue the research by the MC...Go to contribution page
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Dr Attila Pasztor (University of Wuppertal, for the Wuppertal-Budapest collaboration)29/07/2016, 18:10We give a preliminary estimate of the shear viscosity and the sound attenuation length in a pure SU(3) gluon plasma, using an improved anisotropic gauge action. We use Wilson-flow for anisotropy tuning, shifted boundary conditions for renormalization, and a multilevel algorithm for the measurement of the energy-momentum tensor correlators. We also look at the continuum limit of the momenta of...Go to contribution page
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Prof. Claudio Pica (University of Southern Denmark)30/07/2016, 09:00After the discovery of the Higgs boson, the primary objective of the Large Hadron Collider (LHC) experiments is to identify new physics beyond the Standard Model (SM). In fact, both ATLAS and CMS are providing precision tests of the Higgs sector and tantalizing hints of new, unexpected resonances. One of the most intriguing possibilities would be the discovery of non-perturbative phenomena...Go to contribution page
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Dr Enrico Rinaldi (LLNL)30/07/2016, 09:45Models of composite dark matter, originating from a new strongly coupled dark sector, have a very interesting phenomenology. To make robust predictions in these models one often needs to investigate non-perturbative effects due to the strong self interactions. Lattice field theory methods and numerical simulations are well suited for this task and contribute to a solid uncertainty...Go to contribution page
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Prof. David Kaplan (Institute for Nuclear Theory)30/07/2016, 10:15I review some of the different approaches that have been pursued in attempting to define chiral gauge theories on the lattice, all of which are procedures for eliminating unwanted mirror fermions from the theory. I then discuss a recently published proposal with D. Grabowska that combines domain wall fermions with gradient flow as a new idea for how to decouple the mirror fermions, and which...Go to contribution page
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Prof. Tony Hey (STFC)30/07/2016, 11:15This talk will discuss three current trends in computing: quantum computers; data-intensive computing and the recent resurgence in AI and Machine Learning; Exascale computing and the end of Moore’s Law. Although Richard Feynman is famous for his Nobel Prize for QED and his Feynman Diagrams, and for his three volume set of Lectures on Physics, it is not so well-known that he gave lectures on...Go to contribution page
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Prof. Peter Boyle (University of Edinburgh)30/07/2016, 11:45I will discuss the evolution of architectures for QCD with a focus on the interplay between architecture, engineering, data motion and algorithms. I also discuss recent progress in performance programming strategies and algorithms.Go to contribution page
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30/07/2016, 12:30
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