Excitations of the nucleon with dynamical fermions

TL;DR

This study measures low-lying nucleon resonances using Bayesian methods, comparing quenched and dynamical fermion results, revealing that the first positive-parity excitation is heavier than its parity partner at the simulated pion masses.

Contribution

It introduces a comparison of nucleon resonance spectra between quenched and dynamical fermion simulations using Bayesian fitting techniques.

Findings

First positive-parity nucleon excitation is heavier than the parity partner.

Mass differences are consistent across the simulated pion masses.

Bayesian fitting effectively extracts resonance spectra.

Abstract

We measure the spectrum of low-lying nucleon resonances using Bayesian fitting methods. We compare the masses obtained in the quenched approximation to those obtained with two flavours of dynamical fermions at a matched lattice spacing. At the pion masses employed in our simulations, we find that the mass of the first positive-parity nucleon excitation is always greater than that of the parity partner of the nucleon.