Nucleon Mass with Highly Improved Staggered Quarks

TL;DR

This paper reports the first lattice-QCD calculation of the nucleon mass using staggered quarks, achieving high precision and controlling all sources of errors, thus enabling more accurate baryon property predictions.

Contribution

It introduces a novel lattice-QCD approach with highly-improved staggered quarks for baryon physics, providing the most precise nucleon mass determination from first principles.

Findings

Nucleon mass computed as 964±16 MeV.

Used three different lattice spacings with physical quark masses.

Achieved high precision with controlled statistical and systematic errors.

Abstract

We present the first computation in a program of lattice-QCD baryon physics using staggered fermions for sea and valence quarks. For this initial study, we present a calculation of the nucleon mass, obtaining $964\pm16$ MeV with all sources of statistical and systematic errors controlled and accounted for. This result is the most precise determination to date of the nucleon mass from first principles. We use the highly-improved staggered quark action, which is computationally efficient. Three gluon ensembles are employed, which have approximate lattice spacings $a=0.09$ fm, $0.12$ fm, and $0.15$ fm, each with equal-mass $u$/$d$, $s$, and $c$ quarks in the sea. Further, all ensembles have the light valence and sea $u$/$d$ quarks tuned to reproduce the physical pion mass, avoiding complications from chiral extrapolations or nonunitarity. Our work opens a new avenue for precise calculations of baryon properties, which are both feasible and relevant to experiments in particle and nuclear physics.