Nucleon axial, scalar, and tensor charges using lattice QCD at the physical pion mass

Hasan, Nesreen; Krieg, Stefan; Syritsyn, Sergey; Pochinsky, Andrew; Negele, John; Green, Jeremy; Meinel, Stefan; Engelhardt, Michael

Preprint/Report

PUBDB-2019-01785

Nucleon axial, scalar, and tensor charges using lattice QCD at the physical pion mass

Hasan, N. ; Green, J. (Corresponding author)DESY* ; Meinel, S. ; Engelhardt, M. ; Krieg, S. ; Negele, J. ; Pochinsky, A. ; Syritsyn, S.

2019

[10.3204/PUBDB-2019-01785]

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Please use a persistent id in citations: doi:10.3204/PUBDB-2019-01785

Report No.: DESY-19-044; arXiv:1903.06487

Abstract: We report on lattice QCD calculations of the nucleon isovector axial, scalar, and tensor charges. Our calculations are performed on two 2+1-flavor ensembles generated using a 2-HEX-smeared Wilson-clover action at the physical pion mass and lattice spacings $a\approx$ 0.116 and 0.093 fm. We use a wide range of source-sink separations - eight values ranging from roughly 0.4 to 1.4 fm on the coarse ensemble and three values from 0.9 to 1.5 fm on the fine ensemble - which allows us to perform an extensive study of excited-state effects using different analysis and fit strategies. To determine the renormalization factors, we use the nonperturbative Rome-Southampton approach and compare RI'-MOM and RI-SMOM intermediate schemes to estimate the systematic uncertainties. Our final results are computed in the MS-bar scheme at scale 2 GeV. The tensor and axial charges have uncertainties of roughly 4%, $g_T=0.972(41)$ and $g_A=1.265(49)$. The resulting scalar charge, $g_S=0.927(303)$, has a much larger uncertainty due to a stronger dependence on the choice of intermediate renormalization scheme and on the lattice spacing.

Keyword(s): nucleon: charge ; charge: axial ; charge: scalar ; charge: tensor ; quark: mass dependence ; quantum chromodynamics ; lattice field theory ; numerical calculations ; quark: Wilson ; fermion: clover ; quark: flavor: 3 ; renormalization: nonperturbative ; current: vector ; continuum limit ; nucleon ; lattice ; nonperturbative ; excited state ; isovector