Nucleon, Delta and Omega excited state spectra at three pion mass values

TL;DR

This study uses lattice QCD to compute the excited state spectra of nucleon, delta, and omega baryons at three different pion masses, comparing results with experimental data to validate the approach.

Contribution

It presents new lattice QCD calculations of excited baryon spectra at multiple pion masses using a variational method with an extensive operator basis.

Findings

Reasonable agreement with experimental spectra for nucleon excited states

Successful application of variational method with multiple operators

Clear identification of six energies per irreducible representation

Abstract

The energies of the excited states of the Nucleon, Delta and Omega are computed in lattice QCD, using two light quarks and one strange quark on anisotropic lattices. The calculations are performed at three values of the pion mass: 392(4), 438(3) and 521(3) MeV. We employ the variational method with a basis of about ten interpolating operators enabling six energies to be distinguished clearly in each irreducible representation of the octahedral group. We compare our calculations of nucleon excited states with the low-lying experimental spectrum. There is reasonable agreement for the pattern of states.