Prof.
Urs Wenger
(AEC University of Bern)
7/26/16, 7:00 PM
Algorithms and Machines
Poster
We 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...
Mr
Hwancheol Jeong
(Seoul National University)
7/26/16, 7:00 PM
Chiral Symmetry
Poster
We 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....
Mr
Sheng-Tai Li
(Central China Normal University)
7/26/16, 7:00 PM
Nonzero Temperature and Density
Poster
We 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...
Prof.
Pedro Bicudo
(IST - LISBOA)
7/26/16, 7:00 PM
Nonzero Temperature and Density
Poster
We 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...
Mr
Attilio Cucchieri
(University of São Paulo)
7/26/16, 7:00 PM
Vacuum Structure and Confinement
Poster
We 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...
Thomas Rae
(University of Wuppertal)
7/26/16, 7:00 PM
Hadron Spectroscopy and Interactions
Poster
We 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...
Dr
Azusa Yamaguchi
(Software Architect), Prof.
Peter Boyle
(University of Edinburgh)
7/26/16, 7:00 PM
Algorithms and Machines
Poster
Hierarchically 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...
Mr
Matthew Kirk
(IPPP, Durham University)
7/26/16, 7:00 PM
Weak Decays and Matrix Elements
Poster
We 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.
Mr
Joni Suorsa
(University of Helsinki, Helsinki Institute of Physics)
7/26/16, 7:00 PM
Physics Beyond the Standard Model
Poster
We 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.
Mr
Benjamin Jaedon Choi
(Seoul National University / Lattice Gauge Theory Research Center)
7/26/16, 7:00 PM
Standard Model Parameters and Renormalization
Poster
We 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.
Dr
Marina Krstic Marinkovic
(CERN)
7/26/16, 7:00 PM
Algorithms and Machines
Poster
The 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...
Mr
Stefan Hofmann (Unversity of Regensburg)
(German)
7/26/16, 7:00 PM
Hadron Spectroscopy and Interactions
Poster
We 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...
Prof.
Tetsuya Onogi
(Osaka University)
7/26/16, 7:00 PM
Nonzero Temperature and Density
Poster
The 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.
Prof.
Ken-ichi Ishikawa
(Hiroshima University)
7/26/16, 7:00 PM
Nonzero Temperature and Density
Poster
We 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...
Dr
Hideo Matsufuru
(High Energy Accelerator Research Organization (KEK))
7/26/16, 7:00 PM
Applications Beyond QCD
Poster
In 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...
Prof.
Huey-Wen Lin
(Michigan State University)
7/26/16, 7:00 PM
Applications Beyond QCD
Poster
We 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...
Prof.
Weonjong Lee
(Seoul National University)
7/26/16, 7:00 PM
Weak Decays and Matrix Elements
Poster
We 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 $V_{cb}$.
Raza Sufian
(University of Kentucky, United States)
7/26/16, 7:00 PM
Hadron Structure
Poster
We 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) = -...
Prof.
Christine Davies
(University of Glasgow)
7/26/16, 7:00 PM
Hadron Spectroscopy and Interactions
Poster
We 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...
Mr
Felix Erben
(University Mainz)
7/26/16, 7:00 PM
Hadron Spectroscopy and Interactions
Poster
Results 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...
Mr
Sungwoo Park
(Seoul National University)
7/26/16, 7:00 PM
Hadron Spectroscopy and Interactions
Poster
We 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....
Dr
Shinji Takeda
(Kanazawa University)
7/26/16, 7:00 PM
Nonzero Temperature and Density
Poster
We 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...
Dr
Igor Bogolubsky
(Joint Institute for Nuclear Research)
7/26/16, 7:00 PM
Vacuum Structure and Confinement
Poster
We 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.
Ms
Ouraman Hajizadeh
(University of Graz)
7/26/16, 8:00 PM
Nonzero Temperature and Density
Poster
G2-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...
Prof.
Kostas Orginos
(College of William and Mary/JLAB)
7/26/16, 8:00 PM
Hadron Structure
Poster
Results 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...
Sara Tähtinen
(University of Helsinki, Helsinki Institute of Physics)
7/26/16, 8:00 PM
Physics Beyond the Standard Model
Poster
It 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...
Ms
Julia Kettle
(University of Edinburgh)
7/26/16, 8:00 PM
Physics Beyond the Standard Model
Poster
I present preliminary results for Kaon Mixing Beyond the Standard Model at the physical point.
Mr
Kevin Eckert
(WWU Muenster)
7/26/16, 8:00 PM
Weak Decays and Matrix Elements
Poster
We 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...
Mr
Sebastian Schmalzbauer
(Goethe-Universität Frankfurt, Universität Regensburg)
7/26/16, 8:00 PM
Nonzero Temperature and Density
Poster
We 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...
Dr
Ion-Olimpiu Stamatescu
(I.T.P., University Heidelberg)
7/26/16, 8:00 PM
Theoretical Developments
Poster
A 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.
Mr
Marcin Szyniszewski
(Lancaster University)
7/26/16, 8:00 PM
Applications Beyond QCD
Poster
The 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...
Ms
Argia Rubeo
(TCD (Trinity College Dublin))
7/26/16, 8:00 PM
Theoretical Developments
Poster
The 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...
Mr
Jaehoon Leem
(Seoul National University)
7/26/16, 8:00 PM
Weak Decays and Matrix Elements
Poster
The 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...
Dr
YIBO Yang
(university of Kentucky)
7/26/16, 8:00 PM
Hadron Structure
Poster
We 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...
Tereza Mendes
(University of São Paulo)
7/26/16, 8:00 PM
Nonzero Temperature and Density
Poster
We 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...
Mr
Bernhard Lang
(University Regensburg)
7/26/16, 8:00 PM
Hadron Spectroscopy and Interactions
Poster
Hadrons 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].
Mr
Francesco Scardino
(University of Rome "La Sapienza")
7/26/16, 8:00 PM
Hadron Spectroscopy and Interactions
Poster
We 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...
Mr
Suman Baral
(Baylor University)
7/26/16, 8:00 PM
Algorithms and Machines
Poster
Lattice 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...
Dr
Hiroshi Ohki
(RIKEN BNL Research Center),
Sergey Syritsyn
(Jefferson Lab)
7/26/16, 8:00 PM
Physics Beyond the Standard Model
Poster
We 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.
Dr
Takashi UMEDA
(Hiroshima Univ.)
7/26/16, 8:00 PM
Nonzero Temperature and Density
Poster
We 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...
Mr
Eduardo Ibanez Bribian
(Instituto de Fisica Teorica UAM-CSIC)
7/26/16, 8:00 PM
Theoretical Developments
Poster
We 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....
Mr
Peter Georg
(University of Regensburg)
7/26/16, 8:00 PM
Algorithms and Machines
Poster
On 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...
Dr
Daniel Mohler
(Helmholtz-Institut Mainz)
7/26/16, 8:00 PM
Hadron Spectroscopy and Interactions
Poster
We 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...
Ms
Aya Kagimura
(Osaka University)
7/26/16, 8:00 PM
Nonzero Temperature and Density
Poster
The 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....
