Studies of nucleon isovector structure with the PACS10 superfine lattice

TL;DR

This study uses large-scale lattice QCD simulations at physical quark masses to precisely compute nucleon axial-vector, induced pseudoscalar, and pion-nucleon couplings, analyzing systematic uncertainties across multiple lattice spacings.

Contribution

First comprehensive lattice QCD analysis of nucleon isovector structure at physical point with superfine lattice spacing, including systematic uncertainty assessment.

Findings

Consistent nucleon axial-vector coupling with experimental values.

Quantitative determination of induced pseudoscalar and pion-nucleon couplings.

Assessment of systematic uncertainties across different lattice spacings.

Abstract

We present the results for the nucleon axial-vector, induced pseudoscalar and pion-nucleon couplings obtained from 2+1 flavor lattice QCD at the physical point with a large spatial extent of about 10 fm. Our calculations are performed with the PACS10 gauge configurations generated by the PACS Collaboration with the six stout-smeared $O(a)$ improved Wilson-clover quark action and Iwasaki gauge action at $\beta$ = 1.82, 2.00 and 2.20 corresponding to lattice spacings of 0.09 fm (coarse), 0.06 fm (fine) and 0.04 fm (superfine), respectively. We first evaluate the value of the nucleon axial-vector coupling. In addition, the induced pseudoscalar and pion-nucleon couplings from the induced pseudoscalar form factor are also investigated. Combining the results obtained from the all of our coarse, fine and superfine lattices, we finally discuss the systematic uncertainties in our calculation based on the comparison with both of the experimental values and lattice QCD results provided by the other collaborations.