Spin-3/2 Baryons in Lattice QCD

TL;DR

This paper reports the first lattice QCD calculations of spin-3/2 baryon masses using a novel fat-link clover fermion action, revealing detailed mass spectra and level orderings consistent with experimental data.

Contribution

It introduces a new fat-link clover fermion action for lattice QCD and applies it to compute spin-3/2 baryon masses with improved signals and agreement with empirical observations.

Findings

Strong signal for J^P=3/2^- state in isospin-1/2 sector

Good agreement of 1/2^+ mass with previous nucleon simulations

Observed mass splittings and level orderings in Delta states

Abstract

We present first results for masses of spin-3/2 baryons in lattice QCD, using a novel fat-link clover fermion action in which only the irrelevant operators are constructed using fat links. In the isospin-1/2 sector, we observe, after appropriate spin and parity projection, a strong signal for the J^P=3/2^- state, and find good agreement between the 1/2^+ mass and earlier nucleon mass simulations with a spin-1/2 interpolating field. For the isospin-3/2 Delta states, clear mass splittings are observed between the various 1/2^+/- and 3/2^+/- channels, with the calculated level orderings in good agreement with those observed empirically.