Charmonium-Glueball spectroscopy with improved hadron creation operators

TL;DR

This paper develops improved hadron creation operators for lattice QCD to better resolve and identify the composition of scalar glueball and charmonium states, enhancing spectral analysis accuracy.

Contribution

It introduces novel derivative-based meson and glueball operators that improve sampling of energy eigenstates and clarify state compositions in lattice QCD spectroscopy.

Findings

Identified the lightest iso-scalar state as glueball-dominated 0^{++}

Resolved the low-lying spectrum of scalar glueball and charmonium mixing

Demonstrated advantages of new operators in spectral analysis

Abstract

Construction of creation operators which can properly sample the underlying energy eigenstates remains a fundamental first step in lattice QCD spectroscopy calculations, particularly when the spectrum includes states with different composition such as mesons, glueballs, multi-particle states, etc. We tackle this issue in the study of the scalar glueball and charmonium mixing, where we use improved operators for both types of states to resolve the low-lying spectrum and identify the dominant composition of each state in a mass regime where the glueball is stable. We include derivative-based meson operators combined with distillation profiles, as well as glueball operators built from the chromo-magnetic field and its derivatives which retain angular momentum information from their continuum counterparts. We comment on the advantages of these operators, particularly on the construction and implementation of the glueball ones, thanks to which we identify the lightest iso-scalar state as glueball-dominated $0^{++}$.