Finite-size scaling in nucleon axial charge from 2+1-flavor DWF lattice QCD

2012/12/13 by Lin, Meifeng, Ohta, Shigemi
#FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)

paper · doi:10.48550/arxiv.1212.3235

Abstract

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 volume (L = 4.6 fm)³. The result from the ensemble with m_π= 250 MeV pion mass, corresponding to the finite-size scaling parameter m_πL ∼ 5.8, agrees well with an earlier result at a^-1=1.7 GeV, L = 2.8 fm, and m_π= 420 MeV, with similar m_πL. This suggests the systematic error from excited-state contamination is small in both ensembles and about 10-% deficit in g_A we are observing is likely a finite-size effect that scales with m_πL. We also report the result from the lighter, m_π= 170 MeV ensemble.

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• Nucleon isovector charges from physical mass domain-wall QCD
• Nucleon structure from 2+1f dynamical DWF lattice QCD at nearly physical pion mass
• An accurate calculation of the nucleon axial charge with lattice QCD