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We investigate the pion-mass dependence of the nucleon mass within the covariant SU(2) baryon chiral perturbation theory up to order p4 with and without explicit Delta(1232) degrees of freedom. We fit lattice QCD data from several…

High Energy Physics - Phenomenology · Physics 2015-06-18 L. Alvarez-Ruso , T. Ledwig , J. Martin Camalich , M. J. Vicente Vacas

The pion-mass dependence of the nucleon mass within the covariant SU(2) baryon chiral perturbation theory both without and with explicit Delta(1232) degrees of freedom up to order p^4 is investigated. By fitting to lattice QCD data in 2 and…

High Energy Physics - Phenomenology · Physics 2013-10-18 L. Alvarez-Ruso , T. Ledwig , J. Martin Camalich , M. J. Vicente-Vacas

We present results on the light, strange and charm nucleon scalar and tensor charges from lattice QCD, using simulations with $N_f=2$ flavors of twisted mass Clover-improved fermions with a physical value of the pion mass. Both connected…

Nucleon weak matrix elements can be extracted from nucleon correlation functions with lattice QCD simulations. The signal-to-noise ratio prohibits the analysis at large source-sink separations and as a consequence, excited state…

High Energy Physics - Lattice · Physics 2024-06-03 Lorenzo Barca , Gunnar Bali , Sara Collins

We analyze Nf=2 nucleon mass data with respect to their dependence on the pion mass down to mpi = 157 MeV and compare it with predictions from covariant baryon chiral perturbation theory (BChPT). A novel feature of our approach is that we…

It has been argued that the leading scalar-isoscalar WIMP-nucleus interactions receive parametrically enhanced contributions in the context of nuclear effective field theories. These contributions arise from meson-exchange currents (MECs)…

High Energy Physics - Phenomenology · Physics 2015-03-19 S. R. Beane , S. D. Cohen , W. Detmold , H. -W. Lin , M. J. Savage

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

Previous extrapolations of lattice QCD results for the nucleon mass to the physically relevant region of small quark masses, using chiral effective field theory, are extended and expanded in several directions. A detailed error analysis is…

High Energy Physics - Lattice · Physics 2007-05-23 M. Procura , B. U. Musch , T. Wollenweber , T. R. Hemmert , W. Weise

The nucleon-pion-state contribution to QCD two-point and three-point functions used in lattice calculations of the nucleon axial form factors are studied in chiral perturbation theory. For small quark masses this contribution is expected to…

High Energy Physics - Lattice · Physics 2019-04-03 Oliver Bar

We study the performance of all-mode-averaging (AMA) when used in conjunction with a locally deflated SAP-preconditioned solver, determining how to optimize the local block sizes and number of deflation fields in order to minimize the…

High Energy Physics - Lattice · Physics 2016-11-21 Georg von Hippel , Thomas D. Rae , Eigo Shintani , Hartmut Wittig

We present new N_f=2 data for the nucleon generalized form factors, varying volume, lattice spacing and pion mass, down to 150 MeV. We also give an update of our direct calculation of the nucleon sigma term for a range of pion mass values…

High Energy Physics - Lattice · Physics 2013-12-04 G. S. Bali , S. Collins , B. Gläßle , M. Göckeler , J. Najjar , R. Rödl , A. Schäfer , R. Schiel , W. Söldner , A. Sternbeck , P. Wein

We report the current status of the on-going lattice-QCD calculations of nucleon isovector axial charge, g_A, using the RBC/UKQCD 2+1-flavor dynamical domain-wall fermion ensembles at lattice cutoff of about a^{-1}=1.4 GeV in a spatial…

High Energy Physics - Lattice · Physics 2019-08-15 Meifeng Lin , Shigemi Ohta

We investigate an improved method to extract nucleon matrix elements from lattice 3-point functions using a generalized eigenvalue problem (GEVP) with nucleon and pion-nucleon interpolating fields. Our method avoids the computation of the…

High Energy Physics - Lattice · Physics 2024-12-11 Constantia Alexandrou , Giannis Koutsou , Yan Li , Marcus Petschlies , Ferenc Pittler

In this work we present the isovector flavor combination for the nucleon tensor charge extracted from lattice QCD simulations using overlap fermions on $N_f=2+1$ domain-wall configurations. The pion mass dependence is studied using six…

High Energy Physics - Lattice · Physics 2020-05-13 Derek Horkel , Yujiang Bi , Martha Constantinou , Terrence Draper , Jian Liang , Keh-Fei Liu , Zhaofeng Liu , Yi-Bo Yang

We present an update of our analysis [1] which includes additional ensembles at different quark masses, lattice spacings and volumes, all with high statistics. We use $N_f=2$ mass-degenerate quark flavours, employing the non-perturbatively…

We determine generalized form factors of the nucleon from lattice simulations with $N_f = 2$ mass-degenerate non-perturbatively improved Wilson-Sheikholeslami-Wohlert fermions down to a pion mass of 150 MeV. We also present the resulting…

High Energy Physics - Lattice · Physics 2016-01-20 Gunnar Bali , Sara Collins , Meinulf Göckeler , Rudolf Rödl , Andreas Schäfer , Andre Sternbeck

We evaluate the light, strange and charm scalar content of the nucleon using one lattice QCD ensemble generated with two degenerate light quarks with mass fixed to their physical value. We use improved techniques to evaluate the…

We present a dedicated analysis of the influence of excited states on the calculation of nucleon matrix elements. This calculation is performed at a fixed value of the lattice spacing, volume and pion mass that are typical of contemporary…

High Energy Physics - Lattice · Physics 2015-05-30 Simon Dinter , Constantia Alexandrou , Martha Constantinou , Vincent Drach , Karl Jansen , Dru B. Renner

We present 2+1 flavor Lattice QCD calculations of the nucleon scalar and tensor charges. Using the BMW clover-improved Wilson action with pion masses between 150 and 350 MeV and three source-sink separations between 0.9 and 1.4 fm, we…

High Energy Physics - Lattice · Physics 2013-05-30 J. R. Green , J. W. Negele , A. V. Pochinsky , S. N. Syritsyn , M. Engelhardt , S. Krieg

The energies of the excited states of the Nucleon, Delta and Omega are computed in lattice QCD, using two light quarks and one strange quark on anisotropic lattices. The calculations are performed at three values of the pion mass: 392(4),…