Initial nucleon structure results with chiral quarks at the physical point

TL;DR

This paper presents initial results on nucleon structure using lattice QCD with chiral quarks at the physical point, focusing on vector and axial-vector form factors, axial charge, and quark momentum fraction.

Contribution

It introduces a lattice QCD calculation of nucleon structure with 2+1 dynamical M"obius domain wall fermions at the physical point, employing advanced acceleration techniques to improve accuracy and efficiency.

Findings

Estimated 10% accuracy for $g_A$ and $<x>_{u-d}$, aiming for 5%

Used low-eigenmode deflation and all-mode-averaging for cost reduction

Presented a method for optimal AMA parameter selection

Abstract

We report initial nucleon structure results computed on lattices with 2+1 dynamical M\"obius domain wall fermions at the physical point generated by the RBC and UKQCD collaborations. At this stage, we evaluate only connected quark contributions. In particular, we discuss the nucleon vector and axial-vector form factors, nucleon axial charge and the isovector quark momentum fraction. From currently available statistics, we estimate the stochastic accuracy of the determination of $g_A$ and $<x>_{u-d}$ to be around 10%, and we expect to reduce that to 5% within the next year. To reduce the computational cost of our calculations, we extensively use acceleration techniques such as low-eigenmode deflation and all-mode-averaging (AMA). We present a method for choosing optimal AMA parameters.