Low-lying Odd-parity States of the Nucleon in Lattice QCD

TL;DR

This study explores the odd-parity nucleon spectrum at near-physical quark masses using lattice QCD, introducing a novel state-tracking method that successfully aligns with the physical spectrum.

Contribution

It presents the first lattice QCD analysis of odd-parity nucleon states at physical quark masses and introduces a new method for tracking energy eigenstates across quark mass variations.

Findings

Two lowest-energy states match the physical spectrum.

The novel state-tracking method effectively follows state evolution.

Results are consistent with experimental nucleon spectrum.

Abstract

The world's first examination of the odd-parity nucleon spectrum at light quark masses in 2+1 flavor lattice QCD is presented. Configurations generated by the PACS-CS collaboration and made available through the ILDG are used, with the lightest pion mass at 156 MeV. A novel method for tracking the individual energy eigenstates as the quark mass changes is introduced. The success of this approach reveals the flow of the states towards the physical masses. Using the correlation matrix method, the two lowest-energy states revealed are found to be in accord with the physical spectrum of Nature.