Staggered Baryon Operators with Flavor SU(3) Quantum Numbers

TL;DR

This paper develops a new set of baryon operators for staggered lattice QCD that transform under SU(3) flavor and geometrical symmetry groups, enabling more precise calculations of baryon spectra in 2+1 flavor simulations.

Contribution

It introduces a comprehensive construction of maximally local baryon operators transforming under SU(3) x GTS, facilitating improved mass extraction of baryon resonances in staggered QCD.

Findings

Operators can be used to extract lightest baryon masses

Enables clean 2+1 flavor baryon spectrum calculations

Supports analysis of spin-1/2 and spin-3/2 resonances

Abstract

The construction of the first baryon operators for staggered lattice QCD exploited the taste symmetry to emulate physical quark flavor; contemporary 2+1 flavor simulations explicitly include three physical quark flavors and necessitate interpreting a valence sector with twelve quarks. After discussing expected features of the resulting baryon spectrum, I consider the spectra of operators transforming irreducibly under SU(3)xGTS, the direct product of flavor SU(3) and the geometrical time-slice group of the 1-flavor staggered theory. I then describe the construction of a set of maximally local baryon operators transforming irreducibly under SU(3)xGTS and enumerate this set. In principle, the operators listed here could be used to extract the masses of all the lightest spin-1/2 and spin-3/2 baryon resonances of staggered QCD. Using appropriate operators from this set in partially quenched simulations should allow for particularly clean 2+1 flavor calculations of the masses of the nucleon and the lightest decuplet.