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We present an analysis of hadronic spectroscopy for Wilson valence quarks with dynamical staggered fermions at lattice coupling $6/g^2 = \beta=5.6$ at sea quark mass $am_q=0.01$ and 0.025, and of Wilson valence quarks in quenched…

We present updated results for the nucleon axial charge and electromagnetic (EM) form factors, which include a significant increase in statistics for all ensembles (up to 4000 measurements), as well as the addition of ensembles with pion…

High Energy Physics - Lattice · Physics 2014-04-09 B. Jäger , T. D. Rae , S. Capitani , M. Della Morte , D. Djukanovic , G. von Hippel , B. Knippschild , H. B. Meyer , H. Wittig

The latest results from the Twisted-Mass collaboration on disconnected diagrams at the physical value of the pion mass are presented. In particular, we focus on the sigma terms, the axial charges and the momentum fraction, all of them for…

The current status of some nucleon isovector observables, the vector charge, \(g_V\), axial charge, \(g_A\), quark momentum fraction, \(\langle x \rangle_{u-d}\), and quark helicity fraction, \(\langle x \rangle_{\Delta u - \Delta d}\),…

High Energy Physics - Lattice · Physics 2019-08-14 Shigemi Ohta

We present results from simulations of lattice QCD using two flavors of dynamical Wilson fermions at a lattice coupling $\beta=5.3$ on $16^3 \times 32$ lattices at two hopping parameters, $\kappa=0.1670$ and $0.1675$, leading to $m_\pi…

High Energy Physics - Lattice · Physics 2009-10-22 K. M. Bitar

We develop a generalization of low-mode averaging in which the number of low quark modes of the Dirac operator required for a constant variance reduction can be kept independent of the volume by exploiting their local coherence. Typically…

High Energy Physics - Lattice · Physics 2024-12-10 Roman Gruber , Tim Harris , Marina Krstic Marinkovic

Analyses on possible systematics in some isovector nucleon observables in the RBC+UKQCD 2+1-flavor dynamical domain-wall fermion (DWF) lattice-QCD are presented. The vector charge, axial charge, quark momentum and helicity fractions, and…

High Energy Physics - Lattice · Physics 2014-10-31 Shigemi Ohta

We employ dimension-4 operators to improve the local vector and axial-vector currents and calculate the nucleon isovector axial coupling $g^3_A$ with overlap valence on $2+1$-flavor Domain Wall Fermion sea. Using the equality of $g^3_A$…

High Energy Physics - Lattice · Physics 2018-11-05 Jian Liang , Yi-Bo Yang , Keh-Fei Liu , Andrei Alexandru , Terrence Draper , Raza Sabbir Sufian

We discuss methods for the calculation of disconnected diagrams and their application to various form factors of the nucleon. In particular, we present preliminary results for the strange contribution to the scalar and axial form factors,…

High Energy Physics - Lattice · Physics 2008-11-26 Ronald Babich , Richard Brower , Michael Clark , George Fleming , James Osborn , Claudio Rebbi

Results for the disconnected contributions to matrix elements of the vector current and scalar density have been obtained for the nucleon from the Wilson action at beta=6 using a stochastic estimator technique and 2000 quenched…

High Energy Physics - Lattice · Physics 2009-11-07 Randy Lewis , W. Wilcox , R. M. Woloshyn

We perform the non-perturbative renormalization of matrix elements of the static-light axial current by a computation of its scale dependence in lattice QCD with two flavours of massless O(a) improved Wilson quarks. The regularization…

High Energy Physics - Lattice · Physics 2010-10-27 Michele Della Morte , Patrick Fritzsch , Jochen Heitger

This talk presents results of weak matrix elements calculated from simulations done on 170 $32^3 \times 64$ lattices at $\beta = 6.0$ using quenched Wilson fermions. We discuss the extraction of pseudoscalar decay constants $f_\pi$, $f_K$,…

High Energy Physics - Lattice · Physics 2007-05-23 Rajan Gupta , Tanmoy Bhattacharya

The form factors for the semileptonic decays of heavy-light pseudoscalar mesons of the type $D \to Ke\nu$ are studied in quenched lattice QCD at $\beta=6.0$ using Wilson fermions. We explore new numerical techniques for improving the signal…

High Energy Physics - Lattice · Physics 2007-05-23 Rajan Gupta , Tanmoy Bhattacharya , David Daniel

In this paper we consider the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and Non-Relativistic QCD (NRQCD) to three-loop order in perturbation theory. We evaluate the fermionic corrections containing a…

High Energy Physics - Phenomenology · Physics 2008-11-26 P. Marquard , J. H. Piclum , D. Seidel , M. Steinhauser

SU(3) gauge theory with eight massless fundamental fermions seems to be near the conformal boundary, and is a candidate theory of walking technicolor. Along the series of study by LatKMI collaboration using HISQ fermions, S-parameter and…

We report on the use of a stochastic trace estimator algorithm, based on mutually unbiased bases, for evaluating the trace of a matrix differential operator appearing in the context of lattice simulations for the discretized superstring…

High Energy Physics - Lattice · Physics 2022-05-18 Valentina Forini , Bjoern Leder , Nils Wauschkuhn

We calculate both connected and disconnected contribution to the $\pi$-$N$ $\sigma$-term in quenched lattice QCD with Wilson quark action on a $12^3\times 20$ lattice at $\beta=5.7$. The latter is evaluated with the aid of the variant wall…

High Energy Physics - Lattice · Physics 2009-10-22 M. Fukugita , Y. Kuramashi , M. Okawa , A. Ukawa

Due to improvements in computer performance and algorithms, the rapidly increasing cost for unquenched Wilson-type fermions with lighter quarks has been ameliorated and new simulations are now possible. Here we present results using two…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , R. Horsley , Y. Nakamura , D. Pleiter , P. E. L. Rakow , G. Schierholz , W. Schroers , T. Streuer , H. Stüben , J. M. Zanotti

A non-perturbative determination of the axial current improvement coefficient cA is performed with two flavors of dynamical improved Wilson fermions and plaquette gauge action. The improvement condition is formulated with Schroedinger…

High Energy Physics - Lattice · Physics 2008-11-26 Michele Della Morte , Roland Hoffmann , Rainer Sommer

We present results of our ongoing determination of string breaking in full QCD with N_f=2 Wilson fermions. Our investigation of the fission of the static quark-antiquark string into a static-light meson-antimeson system is based on…

High Energy Physics - Lattice · Physics 2009-12-15 G. S. Bali , Th. Duessel , Th. Lippert , H. Neff , Z. Prkacin , K. Schilling