Nucleon spin and quark content at the physical point

TL;DR

This paper reports on lattice QCD simulations near the physical pion mass to determine the nucleon's spin structure and quark content, including axial charge and sigma-terms, using advanced computational methods.

Contribution

It introduces improved techniques for accurately calculating both connected and disconnected contributions to nucleon properties at the physical point.

Findings

Results for axial charge and quark/gluon momentum fractions

Quantitative values for light, strange, and charm sigma-terms

Enhanced methods for lattice QCD calculations

Abstract

We present results on the spin and quark content of the nucleon using $N_f=2$ twisted mass clover-improved fermion simulations with a pion mass close to its physical value. We use recently developed methods to obtain accurate results for both connected and disconnected contributions. We provide results for the axial charge, quark and gluon momentum fraction as well as the light, strange and charm $\sigma$-terms.