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Related papers: Exploring two non-perturbative definitions of $c_A…

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We present results for the non-perturbative determination of the improvement and renormalization factors of the isovector axial current for lattice QCD with two flavors of dynamical Wilson quarks. The improvement and normalization…

High Energy Physics - Lattice · Physics 2007-05-23 Roland Hoffmann , Michele Della Morte , Francesco Knechtli , Rainer Sommer , Ulli Wolff

By considering the local vector current between nucleon states and imposing charge conservation, we determine its renormalisation constant and quark mass improvement coefficient for Symanzik $O(a)$ improved Wilson fermions. The computation…

High Energy Physics - Lattice · Physics 2008-11-26 T. Bakeyev , M. Gockeler , R. Horsley , D. Pleiter , P. E. L. Rakow , G. Schierholz , H. Stuben

Determining the role of initial conditions in the late time evolution is a key issue for the theory of nonequilibrium dynamics of isolated quantum systems. Here we extend the theory of quantum quenches to the case in which before the quench…

Statistical Mechanics · Physics 2023-09-13 Gesualdo Delfino , Marianna Sorba

A finite-size technique is employed to compute the normalization constant $Z_A$ of the isovector axial current in lattice QCD. The calculation is carried out in the quenched approximation for values of the bare gauge coupling $g_0$ ranging…

High Energy Physics - Lattice · Physics 2016-09-01 Martin Lüscher , Stefan Sint , Rainer Sommer , Hartmut Wittig

The conservation of the isovector axial current in lattice QCD with massless Wilson quarks is studied to one-loop order of perturbation theory. Following a strategy described in a previous publication, the O($a$) counterterm required for…

High Energy Physics - Lattice · Physics 2016-08-15 M. Lüscher , P. Weisz

We present results for the mass spectrum and decay constants using non-perturbatively O(a) improved Wilson fermions. Three values of $\beta$ and 30 different quark masses are used to obtain the chiral and continuum limits. Special emphasis…

High Energy Physics - Lattice · Physics 2015-06-25 M. Goeckeler , R. Horsley , D. Petters , D. Pleiter , P. E. L. Rakow , G. Schierholz , P. Stephenson

We present a scaling investigation of renormalized correlation functions in $\Or(a)$--improved quenched lattice QCD. As one observable the renormalized PCAC quark mass is considered, others are constructed such that they become the vector…

High Energy Physics - Lattice · Physics 2009-10-31 Jochen Heitger

Using domain wall fermions, we estimate B_K(mu approx 2 GeV)=0.602(38) in quenched QCD which is consistent with previous calculations. We also find ratios of decay constants that are consistent with experiment, within our statistical…

High Energy Physics - Lattice · Physics 2007-05-23 T. Blum , A. Soni

A completely non-perturbative estimate is given for gA using both quenched and unquenched O(a) improved Wilson fermions. Particular attention is paid to the determination of the axial renormalisation constant, ZA, using the Ward identity…

High Energy Physics - Lattice · Physics 2009-10-31 R. Horsley

We calculate analytically the improvement coefficients of the static axial and vector currents in O(a) improved lattice QCD at one-loop order of perturbation theory. The static quark is described by the hypercubic action, previously…

High Energy Physics - Lattice · Physics 2008-11-26 A. Grimbach , D. Guazzini , F. Knechtli , F. Palombi

As a test of quenched lattice twisted mass QCD, we compute the non-perturbatively O($a$) improved pseudoscalar and vector meson masses and the pseudoscalar decay constant down to $M_{\rm PS}/M_{\rm V} = 0.467(13)$ at $\beta=6$ in large…

High Energy Physics - Lattice · Physics 2015-06-25 M. Della Morte , R. Frezzotti , J. Heitger

We non-perturbatively calculate the scale dependence of the static axial current in the Schroedinger functional scheme by means of a recursive finite-size scaling technique, taking the continuum limit in each step. The bare current in the…

High Energy Physics - Lattice · Physics 2008-11-26 Jochen Heitger , Martin Kurth , Rainer Sommer

We discuss the symmetries of quenched QCD with Wilson fermions, starting from its lagrangian formulation, taking into account the constraints needed for convergence of the ghost-quark functional integral. We construct the corresponding…

High Energy Physics - Lattice · Physics 2009-11-11 Maarten Golterman , Stephen Sharpe , Robert Singleton

We compute the hadron mass spectrum, the quark masses and the meson decay constants in quenched lattice QCD with non-perturbatively $O(a)$ improved Wilson fermions. The calculations are done for two values of the coupling constant, $\beta =…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , R. Horsley , H. Perlt , P. Rakow , G. Schierholz , A. Schiller , P. Stephenson

The quark mass dependence of meson masses and decay constants in N_f=2 QCD is studied at a fixed gauge coupling with different dynamical quark masses. Partially Quenched Wilson Chiral Perturbation Theory (PQWchiPT) is applied to obtain the…

High Energy Physics - Lattice · Physics 2009-11-10 q Collaboration , F. Farchioni , I. Montvay , E. Scholz

By using Numerical Stochastic Perturbation Theory (NSPT), we carry out a quenched two-loop computation of the improvement coefficient $c_A$ associated to the isovector axial current. Within the Schr\"odinger Functional formalism, we compute…

High Energy Physics - Lattice · Physics 2019-02-11 Christian Torrero

We give an introduction to three topics in lattice gauge theory: I. The Schroedinger Functional and O(a) improvement. O(a) improvement has been reviewed several times. Here we focus on explaining the basic ideas in detail and then proceed…

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

The equation of state of QCD at vanishing chemical potential as a function of temperature is determined for two sets of lattice spacings. Coarser lattices with temporal extension of N_t=4 and finer lattices of N_t=6 are used. Symanzik…

High Energy Physics - Lattice · Physics 2009-11-11 Y. Aoki , Z. Fodor , S. D. Katz , K. K. Szabo

We have results from light hadron simulations in quenched QCD at beta=6.0 and 6.2 using non-perturbatively improved Sheikholeslami-Wohlert fermions in an effort to remove all order(a) effects. From looking at hadron masses and splittings…

High Energy Physics - Lattice · Physics 2008-11-26 M. Goeckeler , R. Horsley , H. Perlt , P. Rakow , G. Schierholz , A. Schiller , P. Stephenson

We report on the determination of the improvement coefficient $c_{\rm A}$ for the non-singlet axial-vector current $A^{a}_{\mu}(x)$ in the framework of stabilised Wilson-Clover fermions within three flavour lattice QCD. This is done by…

High Energy Physics - Lattice · Physics 2022-12-22 Patrick Fritzsch , Jochen Heitger , Justus T. Kuhlmann