Glueballs at Physical Pion Mass

TL;DR

This study computes glueball masses at the physical pion mass using lattice QCD with improved error reduction techniques, providing precise results for scalar, tensor, and pseudoscalar glueballs.

Contribution

First lattice QCD calculation of glueball masses at physical pion mass with reduced statistical uncertainties and detailed wave function analysis.

Findings

Glueball masses obtained at physical pion mass.

Wave functions resemble non-relativistic two-gluon systems.

Enhanced signal extraction at early time regions.

Abstract

We study glueballs on two $N_f=2+1$ RBC/UKQCD gauge ensembles with physical quark masses at two lattice spacings. The statistical uncertainties of the glueball correlation functions are considerably reduced through the cluster decomposition error reduction (CDER) method. The Bethe-Salpeter wave functions are obtained for the scalar, tensor and pseudoscalar glueballs by using spatially extended glueball operators defined through the gauge potential $A_\mu(x)$ in the Coulomb gauge. These wave functions show similar features of non-relativistic two-gluon systems, and they are used to optimize the signals of the related correlation functions at the early time regions. Consequently, the ground state masses can be extracted precisely. To the extent that the excited state contamination is not important, our calculation gives glueball masses at the physical pion mass for the first time.