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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

Quantum field theories underlie all of our understanding of the fundamental forces of nature. The are relatively few first principles approaches to the study of quantum field theories [such as quantum chromodynamics (QCD) relevant to the…

High Energy Physics - Lattice · Physics 2010-03-04 F. D. R. Bonnet , Derek B. Leinweber , Anthony G. Williams

Lattice field theory (LFT) is the standard non-perturbative method to perform numerical calculations of quantum field theory. However, the typical bottleneck of fermionic lattice calculations is the inversion of the Dirac matrix. This…

High Energy Physics - Lattice · Physics 2024-01-26 Felipe Attanasio , Marc Bauer , Jelle Dijkstra , Timoteo Lee , Jan M. Pawlowski , Wolfram Pernice

Many observables of interest in lattice QCD are extracted from correlation functions involving the vector current. If Wilson fermions are used, it is therefore of practical importance that, besides the action, the current be O($a$) improved…

High Energy Physics - Lattice · Physics 2015-12-16 Tim Harris , Harvey B. Meyer

We calculate the non-forward quark matrix elements for operators with two covariant derivatives in one-loop lattice perturbation theory using Wilson fermions. These matrix elements are needed in the renormalisation of the second moment of…

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

Lattice QCD calculations of transverse momentum-dependent parton distribution functions (TMDs) in nucleons are presented, based on the evaluation of nucleon matrix elements of quark bilocal operators with a staple-shaped gauge connection.…

Lattice formulations of QCD with Wilson fermions and a chirally twisted quark mass matrix provide an attractive framework for non-perturbative numerical studies. Owing to reparameterization invariance, the limiting continuum theory is just…

High Energy Physics - Lattice · Physics 2009-11-07 R. Frezzotti

We present the first calculation in lattice QCD of the lowest two moments of transverse spin densities of quarks in the nucleon. They encode correlations between quark spin and orbital angular momentum. Our dynamical simulations are based…

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

Results for nucleon matrix elements (arising from moments of structure functions) and form factors from a mixture of runs using Wilson, clover and overlap fermions (both quenched and unquenched) are presented and compared in an effort to…

We present a reduction method for Wilson Dirac fermions with non-zero chemical potential which generates a dimensionally reduced fermion matrix. The size of the reduced fermion matrix is independent of the temporal lattice extent and the…

High Energy Physics - Lattice · Physics 2011-02-18 Andrei Alexandru , Urs Wenger

We discuss how the peculiar properties of maximally twisted Wilson fermions can be exploited to set up a consistent LQCD computational scheme in which the CP-conserving matrix elements of the $\Delta S =1,2$ effective weak Hamiltonian can…

High Energy Physics - Lattice · Physics 2016-09-01 Roberto Frezzotti , Giancarlo Rossi

A representation of the continuum fermionic propagator as a sum of directed random walks on a lattice is presented. Also a random walk representation for the lattice fermionic propagators is developed for the case of the naive, the Wilson,…

High Energy Physics - Lattice · Physics 2007-05-23 Vikram Vyas

QCD is investigated at finite temperature using Wilson fermions in the fixed scale approach. A 2+1 flavor stout and clover improved action is used at four lattice spacings allowing for control over discretization errors. The light quark…

We calculate the third coefficient of the lattice beta function in QCD with Wilson fermions, extending the pure gauge results of Luescher and Weisz; we show how this coefficient modifies the scaling function on the lattice. We also…

High Energy Physics - Lattice · Physics 2009-10-30 B. Alles , C. Christou , A. Feo , H. Panagopoulos , E. Vicari

Large momentum effective field theory provides a new direction for lattice QCD calculations of hadronic structure functions, such as parton distribution functions (PDFs), meson distribution amplitudes, and so on, directly with…

High Energy Physics - Phenomenology · Physics 2018-08-03 Xiaonu Xiong , Thomas Luu , Ulf-G. Meißner

Hasenbusch has proposed splitting the pseudo-fermionic action into two parts, in order to speed-up Hybrid Monte Carlo simulations of QCD. We have tested a different splitting, also using clover-improved Wilson fermions. An additional…

High Energy Physics - Lattice · Physics 2008-11-26 A. Ali Khan , T. Bakeyev , M. Göckeler , R. Horsley , D. Pleiter , P. E. L. Rakow , A. Schäfer , G. Schierholz , H. Stüben

The extreme computational costs of calculating the sign of the Wilson matrix within the overlap operator have so far prevented four dimensional dynamical overlap simulations on realistic lattice sizes, because the computational power…

High Energy Physics - Lattice · Physics 2008-12-18 N. Cundy , S. Krieg , G. Arnold , A. Frommer , Th. Lippert , K. Schilling

We present results on the lower moments of the nucleon generalized parton distri butions within lattice QCD using two dynamical flavors of degenerate twisted mass fermions. Our simulations are performed on lattices with three different…

High Energy Physics - Lattice · Physics 2011-07-05 C. Alexandrou , J. Carbonell , M. Constantinou , P. A. Harraud , P. Guichon , K. Jansen , C. Kallidonis , T. Korzec , M. Papinutto

Partition function zeros steer the critical behavior of a system. Studying four-flavor lattice QCD at finite temperature and density with the Wilson-clover fermion action and the Iwasaki gauge action using a phase-quenched fermion…

High Energy Physics - Lattice · Physics 2013-11-18 Xiao-Yong Jin , Yoshinobu Kuramashi , Yoshifumi Nakamura , Shinji Takeda , Akira Ukawa

I describe how simulations of lattice QCD using the path integral formulation provide the two basic quantum mechanical properties of QCD, its ground state in which correlation functions are calculated, and Fock state wavefunctions between…

High Energy Physics - Lattice · Physics 2023-01-20 Rajan Gupta