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We compute the hadronic running of the electromagnetic and weak couplings in lattice QCD with $N_{\mathrm{f}}=2+1$ flavors of $\mathcal{O}(a)$ improved Wilson fermions. Using two different discretizations of the vector current, we compute…

The non-perturbative $\csw$ determined by the Schr\"{o}dinger functional (SF) method with the RG-improved gauge action in dynamical $N_f=3$ QCD shows a finite volume effect when the numerical simulations are carried out at a constant…

We report on the latest results on the running coupling of two flavour QCD in the Schr\"odinger functional scheme. Results for the step scaling function are obtained from simulations on lattices $L/a=8$ and $L/a=16$ which confirm the first…

High Energy Physics - Lattice · Physics 2009-11-07 M. Della Morte , R. Frezzotti , J. Heitger , F. Knechtli , J. Rolf , R. Sommer , U. Wolff

We explain how masses and matrix elements can be computed in lattice QCD using Schr"odinger functional boundary conditions. Numerical results in the quenched approximation demonstrate that good precision can be achieved. For a statistical…

High Energy Physics - Lattice · Physics 2015-06-25 Marco Guagnelli , Jochen Heitger , Rainer Sommer , Hartmut Wittig

We present an evaluation of the running coupling constant and the quark mass renormalization factor for $N_f=2+1$ QCD. The Schr\"odinger functional scheme is used as the intermediate scheme to carry out non-perturbative running from the low…

High Energy Physics - Lattice · Physics 2019-08-14 Yusuke Taniguchi

SU(2) gauge theory with two fermions transforming under the adjoint representation may appear conformal or almost conformal in the infrared, and is one of the candidate theories for building models for technicolor. Early lattice Monte Carlo…

High Energy Physics - Lattice · Physics 2015-05-20 Tuomas Karavirta , Anne Mykkanen , Jarno Rantaharju , Kari Rummukainen , Kimmo Tuominen

We investigate the low-lying eigenvalues of the improved Wilson-Dirac operator in the Schroedinger functional with two dynamical quark flavors. At a lattice spacing of approximately 0.1 fm we find more very small eigenvalues than in the…

High Energy Physics - Lattice · Physics 2009-11-10 M. Della Morte , R. Hoffmann , F. Knechtli , U. Wolff

We give a full account of the Numerical Stochastic Perturbation Theory method for Lattice Gauge Theories. Particular relevance is given to the inclusion of dynamical fermions, which turns out to be surprisingly cheap in this context. We…

High Energy Physics - Lattice · Physics 2008-11-26 F. Di Renzo , L. Scorzato

We show that it is possible to construct a lattice Schroedinger functional for standard Wilson fermions, where the expectation values of ${\cal R}_5$-even operators are O($a$) improved, up to terms coming from the boundaries.

High Energy Physics - Lattice · Physics 2007-05-23 Roberto Frezzotti , Giancarlo Rossi

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

A comprehensive number of integrals emerging in one-loop computations in a gauge perturbation theory on the lattice with Wilson fermions at $r=1$ is computed using the Burgio--Caracciolo--Pelissetto algorithm and the FORM package. An…

High Energy Physics - Lattice · Physics 2009-02-22 R. N. Rogalyov

Renormalization constants can be computed by means of Numerical Stochastic Perturbation Theory to two/three loops in lattice perturbation theory, both in the quenched approximation and in the full (unquenched) theory. As a case of study we…

High Energy Physics - Lattice · Physics 2009-11-10 F. Di Renzo , A. Mantovi , V. Miccio , L. Scorzato , C. Torrero

We discuss a general strategy to compute the coefficients of QCD chiral Lagrangian by using the lattice regularization of QCD with Wilson fermions. This procedure requires the introduction of an effective Lagrangian for lattice QCD as an…

High Energy Physics - Lattice · Physics 2009-10-28 A. R. Levi , V. Lubicz , C. Rebbi

We determine the three-loop coefficient of the beta function in the asymmetric momentum subtraction scheme in Landau gauge. This scheme is convenient for lattice studies of \alpha_s, the running coupling constant of QCD. We present high…

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

The chirally rotated Schr\"odinger functional ($\chi$SF) with massless Wilson-type fermions provides an alternative lattice regularization of the Schr\"odinger functional (SF), with different lattice symmetries and a common continuum limit…

High Energy Physics - Lattice · Physics 2016-08-17 Mattia Dalla Brida , Stefan Sint , Pol Vilaseca

We present a first numerical study of lattice QCD with O(a) improved Wilson quarks and a chirally twisted mass term. Renormalized correlation functions are derived from the Schroedinger functional and evaluated in an intermediate space-time…

High Energy Physics - Lattice · Physics 2010-02-03 M. Della Morte , R. Frezzotti , J. Heitger , S. Sint

We consider O(a) improvement for two flavor lattice QCD. The improvement term in the action is computed non-perturbatively for a large range of the bare coupling. The position of the critical line and higher order lattice artifacts…

High Energy Physics - Lattice · Physics 2009-10-31 Karl Jansen , Rainer Sommer

We describe an algebraic algorithm which allows to express every one-loop lattice integral with gluon or Wilson-fermion propagators in terms of a small number of basic constants which can be computed with arbitrary high precision. Although…

High Energy Physics - Lattice · Physics 2009-10-28 Giuseppe Burgio , Sergio Caracciolo , Andrea Pelissetto

We present a preliminary result of Nf=2+1 QCD running coupling in Schroedinger functional scheme. We adopted Iwasaki gauge action and non-perturbatively improved Wilson fermion action with clover term. We use seven renormalization scales to…

High Energy Physics - Lattice · Physics 2010-01-21 Yusuke Taniguchi

We have carried out a Schrodinger functional (SF) calculation for the SU(3) lattice gauge theory with two flavors of Wilson fermions in the sextet representation of the gauge group. We find that the discrete beta function, which governs the…

High Energy Physics - Lattice · Physics 2008-11-26 Yigal Shamir , Benjamin Svetitsky , Thomas DeGrand
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