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We determine the strong coupling constant $\alpha_s$ from a lattice calculation of vacuum polarization functions (VPF) in three-flavor QCD with dynamical overlap fermions. Fitting lattice data of VPF to the continuum perturbative formula…

High Energy Physics - Lattice · Physics 2014-09-05 E. Shintani , S. Aoki , H. Fukaya , S. Hashimoto , T. Kaneko , T. Onogi , N. Yamada

We use lattice QCD simulations, with MILC configurations (including vacuum polarization from u, d, and s quarks), to update our previous determinations of the QCD coupling constant. Our new analysis uses results from 6 different lattice…

High Energy Physics - Lattice · Physics 2009-01-08 C. T. H. Davies , K. Hornbostel , I. D. Kendall , G. P. Lepage , C. McNeile , J. Shigemitsu , H. Trottier

We present results by the ALPHA collaboration for the $\Lambda$-parameter in 3-flavour QCD and the strong coupling constant at the electroweak scale, $\alpha_s(m_Z)$, in terms of hadronic quantities computed on the CLS gauge configurations.…

High Energy Physics - Lattice · Physics 2017-01-13 M. Bruno , M. Dalla Brida , P. Fritzsch , T. Korzec , A. Ramos , S. Schaefer , H. Simma , S. Sint , R. Sommer

In this Letter, we provide a determination of the coupling constant in three-flavor quantum chromodynamics (QCD), $\alpha^{\overline{\mathrm{MS}}}_s(\mu)$, for $\overline{\mathrm{MS}}$ renormalization scales $\mu \in (1,\,2)$ GeV. The…

High Energy Physics - Lattice · Physics 2021-01-04 Salvatore Cali , Krzysztof Cichy , Piotr Korcyl , Jakob Simeth

We present estimates of the masses of light quarks using lattice data. Our main results are based on a global analysis of all the published data for Wilson, Sheikholeslami-Wohlert (clover), and staggered fermions, both in the quenched…

High Energy Physics - Lattice · Physics 2008-11-26 Rajan Gupta , Tanmoy Bhattacharya

We explain how scale dependent renormalized quantities can be computed using lattice QCD. Two examples are used: the running coupling and quark masses. A reliable computation of the $\Lambda$-parameter in the quenched approximation is…

High Energy Physics - Phenomenology · Physics 2007-05-23 Rainer Sommer

We determine the leptonic decay constants in three flavor unquenched lattice QCD. We use O(a^2)-improved staggered light quarks and O(a)-improved charm quarks in the Fermilab heavy quark formalism. Our preliminary results, based upon an…

We present a determination of the strange quark mass for two flavours (nf=2) of light dynamical quarks using the axial Ward identity. The calculations are performed on the lattice using O(a) improved Wilson fermions and include a fully…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , R. Horsley , A. C. Irving , D. Pleiter , P. E. L. Rakow , G. Schierholz , H. Stüben , J. M. Zanotti

We pursue a new method, based on lattice QCD, for determining the quantities $\bar{\Lambda}$, $\lambda_1$, and $\lambda_2$ of heavy-quark effective theory. We combine Monte Carlo data for the meson mass spectrum with perturbative…

High Energy Physics - Phenomenology · Physics 2009-10-31 Andreas S. Kronfeld , James N. Simone

We report on the non-perturbative computation of the running coupling of two-flavour QCD in the Schr"odinger functional scheme. The corresponding Lambda-parameter, which describes the coupling strength at high energy, is related to a low…

We calculate the vacuum polarization functions on the lattice using the overlap fermion formulation.By matching the lattice data at large momentum scales with the perturbative expansion supplemented by Operator Product Expansion (OPE), we…

High Energy Physics - Lattice · Physics 2019-08-13 E. Shintani , S. Aoki , T. W. Chiu , S. Hashimoto , T. H. Hsieh , T. Kaneko , H. Matsufuru , J. Noaki , T. Onogi , N. Yamada

We revisit previous determination of the strong coupling constant from moments of quarkonium correlators in (2+1)-flavor QCD. We use previously calculated moments obtained with Highly Improved Staggered Quark (HISQ) action for five…

High Energy Physics - Lattice · Physics 2022-02-10 Peter Petreczky , Johannes Heinrich Weber

We present a high statistics study of the light hadron spectrum and quark masses in QCD with two flavors of dynamical quarks. Numerical simulations are carried out using the plaquette gauge action and the O(a)-improved Wilson quark action…

Comparing perturbative calculations with a lattice computation of the static energy in quantum chromodynamics at short distances, we obtain a determination of the strong coupling alpha_s. Our determination is performed at a scale of around…

High Energy Physics - Phenomenology · Physics 2012-08-27 Xavier Garcia i Tormo

We present results for the light quark masses and the neutral kaon mixing parameter $B_K$ from lattice QCD. Our data set includes lighter than physical light quark masses and 5 lattice spacings so that chiral extrapolation is not necessary…

High Energy Physics - Phenomenology · Physics 2012-07-02 Christian Hoelbling

We compute the ratio Lambda_L/Lambda_MS, where the scale parameter Lambda_L is associated with a lattice formulation of QCD. We consider a 3-parameter family of gluon actions, which are most frequently used for O(a) improvement a` la…

High Energy Physics - Lattice · Physics 2008-11-26 A. Skouroupathis , H. Panagopoulos

We compute the flavorless running coupling constant of QCD from the three gluon vertex in the (regularisation independent) momentum subtraction renormalisation scheme. This is performed on the lattice with high statistics. The expected…

High Energy Physics - Phenomenology · Physics 2010-03-19 Ph. Boucaud , J. P. Leroy , J. Micheli , O. Pène , C. Roiesnel

We complete the non-perturbative calculations of the strange quark mass and the Lambda parameter in two flavor QCD by the ALPHA collaboration. The missing lattice scale is determined via the kaon decay constant, for whose chiral…

High Energy Physics - Lattice · Physics 2015-06-05 Patrick Fritzsch , Francesco Knechtli , Björn Leder , Marina Marinkovic , Stefan Schaefer , Rainer Sommer , Francesco Virotta

A completely non-perturbative estimate is given for the u/d and strange quark masses in quenched QCD using O(a) improved fermions and, for comparison, Wilson fermions. For improved fermions we find m_{u/d}^MSbar(\mu=2 GeV) = 4.4(2) MeV,…

High Energy Physics - Lattice · Physics 2015-06-25 M. Gockeler , R. Horsley , B. Klaus , W. Kurzinger , H. Oelrich , D. Petters , D. Pleiter , P. E. L. Rakow , G. Schierholz , P. Stephenson

We review the long term project of the ALPHA collaboration to compute in QCD the running coupling constant and quark masses at high energy scales in terms of low energy hadronic quantities. The adapted techniques required to numerically…

High Energy Physics - Lattice · Physics 2015-01-09 Rainer Sommer , Ulli Wolff