Spin-3/2 Nucleon and Delta Baryons in Lattice QCD

TL;DR

This paper reports lattice QCD calculations of spin-3/2 baryon masses, revealing signals for various states and mass splittings consistent with experimental observations, using FLIC fermions and advanced projection techniques.

Contribution

First lattice QCD results for spin-3/2 N and Delta baryon masses using FLIC fermions with detailed spin and parity analysis.

Findings

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

Mass splittings between different spin-parity states match experimental data

Good agreement with previous nucleon mass simulations

Abstract

We present first results for masses of spin-3/2 N and Delta baryons in lattice QCD using Fat-Link Irrelevant Clover (FLIC) fermions. Spin-3/2 interpolating fields providing overlap with both spin-3/2 and spin-1/2 states are considered. In the isospin-1/2 sector, we observe, after appropriate spin and parity projection, a strong signal for the J^P=3/2^- state together with a weak but discernible signal for the 3/2^+ state with a mass splitting near that observed experimentally. We also find good agreement between the 1/2^+/- masses and earlier nucleon mass simulations with the standard 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.