Even parity excitations of the nucleon in lattice QCD

TL;DR

This study investigates the spectrum of even parity nucleon excitations using quenched lattice QCD, expanding previous analyses to include more comprehensive data and methods, but finds little evidence of the Roper resonance.

Contribution

The paper introduces an expanded basis of interpolating fields and increased lattice size to improve the analysis of nucleon excitations in quenched lattice QCD.

Findings

Little evidence of the Roper resonance in quenched lattice QCD

Enhanced statistical analysis with more configurations

Extended basis of nucleon interpolating fields

Abstract

We study the spectrum of the even parity excitations of the nucleon in quenched lattice QCD. We extend our earlier analysis by including an expanded basis of nucleon interpolating fields, increasing the physical size of the lattice, including more configurations to enhance statistics and probing closer to the chiral limit. With a review of world lattice data, we conclude that there is little evidence of the Roper resonance in quenched lattice QCD.