Structure and Flow of the Nucleon Eigenstates in Lattice QCD

TL;DR

This paper investigates the excited states of the nucleon in full QCD using lattice simulations, introducing a new technique to track state evolution across different quark masses, especially useful for complex spectra.

Contribution

It presents a novel method for analyzing the intrinsic nature of energy states in lattice QCD, improving the tracking of near-degenerate states across quark masses.

Findings

Successfully determined nucleon excited energy eigenstates in full QCD.

Developed a new technique for tracking state evolution across quark masses.

Enhanced analysis of complex spectra with near-degenerate states.

Abstract

A determination of the excited energy eigenstates of the nucleon, $s=c{1}{2}$, $I={1}{2}$, $N^{\pm}$, is presented in full QCD using 2+1 flavor PACS-CS gauge configurations. The correlation-matrix method is used and is built using standard nucleon interpolators employing smearings at the fermion sources and sinks. We develop and demonstrate a new technique that allows the eigenvectors obtained to be utilized to track the propagation of the intrinsic nature of energy-states from one quark mass to the next. This approach is particularly useful for larger dimension correlation matrices where more near-degenerate energy-states can appear in the spectrum.