Excited-State Hadron Masses from Lattice QCD

TL;DR

This paper advances lattice QCD techniques to compute excited hadron spectra, emphasizing the importance of multi-hadron operators and introducing new stochastic methods for better accuracy.

Contribution

It introduces a novel stochastic approach for low-lying quark modes and demonstrates the feasibility of mixing glueball and multi-hadron operators in lattice QCD.

Findings

Successful implementation of multi-hadron operators

Feasibility of mixing glueball and quark-antiquark operators

Enhanced methods for excited hadron spectrum calculation

Abstract

Progress in computing the spectrum of excited baryons and mesons in lattice QCD is described. Large sets of spatially-extended hadron operators are used. The need for multi-hadron operators in addition to single-hadron operators is emphasized, necessitating the use of a new stochastic method of treating the low-lying modes of quark propagation which exploits Laplacian Heaviside quark-field smearing. A new glueball operator is tested, and computing the mixing of this glueball operator with a quark-antiquark operator and multiple two-pion operators is shown to be feasible.