Nucleon structure from 2+1 flavor lattice QCD near the physical point

TL;DR

This study uses large-volume lattice QCD simulations near the physical pion mass to accurately compute nucleon form factors, providing insights into nucleon structure and testing fundamental symmetries.

Contribution

It presents updated nucleon form factor results from 2+1 flavor lattice QCD near the physical point, including preliminary axial and pseudo-scalar form factors and their theoretical relations.

Findings

Determined nucleon electric radius and magnetic moment with high precision.

Provided preliminary results on axial-vector and pseudo-scalar form factors.

Verified the generalized Goldberger-Treiman relation in lattice QCD.

Abstract

We present an update on our results of nucleon form factors measured on a large-volume lattice $(8.1\rm{fm})^4$ at almost the physical point in 2+1 flavor QCD. The configurations are generated with the stout-smeared $\mathcal{O}(a)$ improved Wilson quark action and Iwasaki gauge action at $\beta = 1.82$, which corresponds to the lattice spacing of 0.085 fm. The pion mass at the simulation point is about 145 MeV. We determine the iso- vector electric radius and magnetic moment from nucleon electric ($G_E$) and magnetic ($G_M$) form factors. We also report on preliminary results of the axial-vector ($F_A$), induced pseudo-scalar ($F_P$) and pseudo-scalar ($G_P$) form factors in order to verify the axial Ward- Takahashi identity in terms of the nucleon matrix elements, which may be called as the generalized Goldberger-Treiman relation.