Nucleon mass, isovector charges and couplings, and isovector form factors calculated in domain-wall lattice QCD at physical mass
ORAL
Abstract
Current status of lattice-QCD numerical calculations by joint LHP and RBC collaborations of nucleon mass, isovector vector and axial vector charges and tensor and scalar couplings, and isovector vector- and axialvector-current form factors using a 2+1-flavor dynamical domain-wall fermions lattice QCD ensemble generated jointly by RBC and UKQCD collaborations will be presented. The lattice spacing is set at about 0.1141(3) fm, and the lattice spatial extent is 48 spacings or about 5.4750(14) fm. The dynamical strange and degenerate up and down quark mass values are set at their essentially physical values to provide the physical Ω mass and a degenerate pion mass of 0.1392(2) GeV. Our nucleon mass estimate is about 0.947(6) GeV. We see a possible indication of contamination from excited states in our calculated isovector vector charge. Compared with the experiment, we observe a small but statistically significant deficit in the calculated isovector axialvector charge. We obtain good signals for isovector tensor coupling but not for scalar coupling. Possible excited-state contaminations in the calculated vector- and axialvector-current form factors are hidden below larger statistical noises. The numerical details of the shape parameters, such as the mean squared radii, the anomalous magnetic moment, or the pseudoscalar coupling, extracted from the form factors, will be given along with their possible impacts on the present and future experiments.
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Publication: PoS (Lattice 2022) 116 <https://pos.sissa.it/430/116/pdf> and the references cited therein. A full paper reporting the results is being drafted.
Presenters
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Shigemi Ohta
KEK, High Energy Accelerator Research Organization
Authors
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Shigemi Ohta
KEK, High Energy Accelerator Research Organization