Conveners
Standard Model Parameters and Renormalization
- Krzysztof Cichy (Goethe-University Frankfurt am Main)
Standard Model Parameters and Renormalization
- Eliana Lambrou (University of Wuppertal)
Standard Model Parameters and Renormalization
- Francesco Knechtli (University of Wuppertal)
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Prof. Stefan Sint (Trinity College Dublin)25/07/2016, 16:45Standard Model Parameters and RenormalizationTalkA 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 Alberto Ramos (CERN)25/07/2016, 17:05Standard Model Parameters and RenormalizationTalkA 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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Prof. Rainer Sommer (NIC @ DESY)25/07/2016, 17:25Standard Model Parameters and RenormalizationTalkThe 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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Dr Eliana Lambrou (University of Wuppertal)25/07/2016, 17:45Standard Model Parameters and RenormalizationTalkWe 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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Mr Ryoichiro Ueno (Graduate School of Science, Hiroshima University)25/07/2016, 18:05Standard Model Parameters and RenormalizationTalkWe 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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Prof. Gerrit Schierholz (DESY)25/07/2016, 18:25Standard Model Parameters and RenormalizationTalkThe 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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Dr Yu Maezawa (YITP, Kyoto University)26/07/2016, 14:00Standard Model Parameters and RenormalizationTalkWe 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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Dr Krzysztof Cichy (Goethe-University Frankfurt am Main)26/07/2016, 14:20Standard Model Parameters and RenormalizationTalkWe 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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Mr David Preti (Instituto de Física Teórica CSIC/UAM)26/07/2016, 14:40Standard Model Parameters and RenormalizationTalkWe 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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Katsumasa Nakayama (Nagoya University)26/07/2016, 15:00Standard Model Parameters and RenormalizationTalkWe 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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Mr Lukas Varnhorst (University of Wuppertal)26/07/2016, 15:20Standard Model Parameters and RenormalizationTalkWe 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, 15:40Standard Model Parameters and RenormalizationTalk[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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Dr Jochen Heitger (University of Muenster, ITP)27/07/2016, 09:00Standard Model Parameters and RenormalizationTalkBased 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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Dr Stefano Piemonte (University of Regensburg)27/07/2016, 09:20Standard Model Parameters and RenormalizationTalkWe 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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Dr Georg von Hippel (University of Mainz)27/07/2016, 09:40Standard Model Parameters and RenormalizationTalkWe 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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Dr Piotr Korcyl (University of Regensburg)27/07/2016, 10:00Standard Model Parameters and RenormalizationTalkWe 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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Ms Ava Khamseh (The University of Edinburgh)27/07/2016, 10:20Standard Model Parameters and RenormalizationTalkA 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