Excited Baryon Spectroscopy from Lattice QCD: Finite Size Effect and Hyperfine Mass Splitting

TL;DR

This paper investigates how finite lattice size affects baryon spectra in quenched lattice QCD, revealing size thresholds for accurate results and peculiar effects on hyperfine mass splittings.

Contribution

It provides detailed analysis of finite-size effects on both ground and excited baryon states, highlighting the importance of lattice size in lattice QCD simulations.

Findings

Lattice size larger than 3 fm is needed for accurate delta state spectra.

Finite-size effects significantly influence hyperfine mass splittings.

Negative-parity nucleon states require larger lattices for reliable results.

Abstract

A study of the finite-size effect is carried out for spectra of both ground-state and excited-state baryons in quenched lattice QCD using Wilson fermions. Our simulations are performed at beta=6.2 with three different spatial sizes, La~1.6, 2.2 and 3.2 fm. It is found that the physical lattice size larger than 3 fm is required for delta states in all spin-parity (J^{P}=1/2^{+/-}, 3/2^{+/-}) channels and also negative-parity nucleon state (J^{P}=1/2^{-}) even in the rather heavy quark mass region. We also find a peculiar behavior of the finite-size effect on the hyperfine mass splittings between the nucleon and the delta in both parity channels.