Nucleon isovector couplings from 2+1 flavor lattice QCD at the physical point

TL;DR

This paper reports on the calculation of nucleon isovector couplings (axial, scalar, tensor) using 2+1 flavor lattice QCD at the physical pion mass, employing large-volume simulations and advanced renormalization techniques.

Contribution

It provides the first precise determination of nucleon isovector couplings at the physical point using large-volume lattice QCD with improved renormalization schemes.

Findings

Results for axial, scalar, and tensor couplings are obtained at the physical pion mass.

The study achieves reduced systematic errors through the RI/SMOM scheme.

Final results are presented in the $ar{MS}$ scheme at 2 GeV.

Abstract

We present results on the axial, scalar and tensor isovector-couplings of the nucleon from 2+1 flavor lattice QCD with physical light quarks ($m_\pi$ = 135 MeV) in large spatial volume of (10.8 fm)$^3$. The calculations are carried out with the PACS10 gauge configurations generated by the PACS Collaboration with the stout-smeared $\mathcal{O}(a)$ improved Wilson fermions and Iwasaki gauge action at $\beta=1.82$ corresponding to the lattice spacing of 0.084 fm. For the renormalization, we use the RI/SMOM scheme, a variant of Rome-Southampton RI/MOM scheme with reduced systematic errors, as the intermediate scheme. We then evaluate our final results in the $\overline{\rm MS}$ scheme at a scale of 2 GeV, using the continuum perturbation theory for the matching scale of RI/SMOM and $\overline{\rm MS}$ schemes and running.