Toward the excited isoscalar meson spectrum from lattice QCD

TL;DR

This paper uses lattice QCD to explore the spectrum of excited isoscalar mesons, including hybrid states, with high statistical precision across various lattice volumes and quark masses.

Contribution

It introduces a detailed lattice QCD study of excited isoscalar mesons, including hybrid states, with improved methods for disconnected contributions and flavor mixing analysis.

Findings

Relatively little mixing between light and strange quarks in most channels.

Reproduction of the SU(3)F octet and singlet structure of eta and eta' mesons.

Identification of exotic and non-exotic hybrid mesons.

Abstract

We report on the extraction of an excited spectrum of isoscalar mesons using lattice QCD. Calculations on several lattice volumes are performed with a range of light quark masses corresponding to pion masses down to about 400 MeV. The distillation method enables us to evaluate the required disconnected contributions with high statistical precision for a large number of meson interpolating fields. We find relatively little mixing between light and strange in most JPC channels; one notable exception is the pseudoscalar sector where the approximate SU(3)F octet, singlet structure of the {\eta}, {\eta}' is reproduced. We extract exotic JPC states, identified as hybrid mesons in which an excited gluonic field is coupled to a color-octet qqbar pair, along with non-exotic hybrid mesons embedded in a qqbar-like spectrum.