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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

The QCD coupling appears in the perturbative expansion of the current-current two-point (vacuum polarization) function. Any lattice calculation of vacuum polarization is plagued by several competing non-perturbative effects at small momenta…

High Energy Physics - Lattice · Physics 2015-10-19 Renwick J. Hudspith , Randy Lewis , Kim Maltman , Eigo Shintani

We obtain a new value for the QCD coupling constant by combining lattice QCD simulations with experimental data for hadron masses. Our lattice analysis is the first to: 1) include vacuum polarization effects from all three light-quark…

High Energy Physics - Lattice · Physics 2009-11-11 Q. Mason , H. D. Trottier , C. T. H. Davies , K. Foley , A. Gray , G. P. Lepage , M. Nobes , J. Shigemitsu

We present a new determination of the strong coupling constant from lattice QCD simulations. We use four different short-distance quantities to obtain the coupling, three different (infrared) meson splittings to tune the simulation…

High Energy Physics - Lattice · Physics 2016-08-24 C. T. H. Davies , K. Hornbostel , G. P. Lepage , P. McCallum , J. Shigemitsu , J. Sloan

We present a determination of the QCD coupling constant, $\alpha_s$, obtained by fitting lattice results for the flavour $ud$ hadronic vacuum polarisation function to continuum perturbation theory. We use $n_f=2+1$ flavours of Domain Wall…

High Energy Physics - Lattice · Physics 2018-07-09 Renwick J. Hudspith , Randy Lewis , Kim Maltman , Eigo Shintani

We present a new determination of the QCD strong coupling constant based on precise lattice calculations of the $\Upsilon$ spectrum. The largest systematic uncertainty in previous such determinations resulted from the absence of vacuum…

High Energy Physics - Phenomenology · Physics 2009-10-28 C. T. H. Davies , K. Hornbostel , G. P. Lepage , A. Lidsey , J. Shigemitsu , J. Sloan

We present a determination of the strong coupling constant and heavy quark masses in (2+1)-flavor QCD using lattice calculations of the moments of the pseudo-scalar quarkonium correlators at several values of the heavy valence quark mass…

High Energy Physics - Lattice · Physics 2019-09-10 P. Petreczky , J. H. Weber

The vacuum polarization due to chiral fermions on a 4--dimensional Euclidean lattice is calculated according to the overlap prescription. The fermions are coupled to weak and slowly varying background gauge and Higgs fields, and the…

High Energy Physics - Theory · Physics 2009-10-28 S. Randjbar--Daemi , J. Strathdee

The strong coupling constant alpha_s(mu_0), taken at a fixed reference scale mu_0, is the single free parameter of QCD and should be known to the highest available precision. The value of alpha_s should also be determined with good accuracy…

High Energy Physics - Lattice · Physics 2017-08-23 Attilio Cucchieri

We compute the vacuum polarization on the lattice using non-perturbatively O(a) improved Wilson fermions. The result is compared with the operator product expansion (OPE).

High Energy Physics - Lattice · Physics 2008-11-26 M. Gockeler , R. Horsley , W. Kurzinger , V. Linke , D. Pleiter , P. E. L. Rakow , G. Schierholz

The contribution from hadronic vacuum polarisation effects is responsible for a large fraction of the theoretical uncertainty in the running of the QED coupling. The current level of uncertainty has become a limitation for electroweak…

High Energy Physics - Lattice · Physics 2014-12-23 Anthony Francis , Gregorio Herdoíza , Hanno Horch , Benjamin Jäger , Harvey B. Meyer , Hartmut Wittig

The static energy is an excellent observable for extracting the strong coupling $\alpha_s$ on the lattice. For short distances, the static energy can be calculated both on the lattice using Wilson line correlators, and with perturbation…

We present a lattice determination of the $\Lambda$ parameter in three-flavor QCD and the strong coupling at the Z pole mass. Computing the nonperturbative running of the coupling in the range from $0.2\,$GeV to $70\,$GeV, and using…

High Energy Physics - Lattice · Physics 2017-09-13 M. Bruno , M. Dalla Brida , P. Fritzsch , T. Korzec , A. Ramos , S. Schaefer , H. Simma , S. Sint , R. Sommer

We compute $\Lambda_{\bar{MS}}$ for two flavors of light dynamical quarks using non-perturbatively $O(a)$ improved Wilson fermions. We improve on a recent calculation by employing Pad\'e-improved two-loop and three-loop perturbation theory…

High Energy Physics - Lattice · Physics 2008-11-26 S. Booth , M. Göckeler , R. Horsley , A. C. Irving , B. Joo , S. Pickles , D. Pleiter , P. E. L. Rakow , G. Schierholz , Z. Sroczynski , H. Stüben

The strong coupling $\alpha_\mathrm{s}$ can be obtained from the static energy as shown in previous lattices studies. For short distances, the static energy can be calculated both on the lattice with the use of Wilson line correlators, and…

We determine the strong coupling constant $\alpha_s(M_Z)$ from the static QCD potential by matching a lattice result and a theoretical calculation. We use a new theoretical framework based on operator product expansion (OPE), where…

High Energy Physics - Phenomenology · Physics 2019-05-24 Hiromasa Takaura , Takashi Kaneko , Yuichiro Kiyo , Yukinari Sumino

We compute the vacuum polarisation on the lattice in quenched QCD using non-perturbatively improved Wilson fermions. Above Q^2 of about 2 GeV^2 the results are very close to the predictions of perturbative QCD. Below this scale we see signs…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , R. Horsley , W. Kürzinger , D. Pleiter , P. E. L. Rakow , G. Schierholz

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

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

In this work we present lattice calculations of the masses of P-wave mesons using Monte Carlo simulations. Our valence fermions are defined by the Wilson action. Our gauge fields are generated with both dynamical staggered fermions at a…

High Energy Physics - Lattice · Physics 2016-08-31 M. Wingate , T. DeGrand , S. Collins , U. M. Heller
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