Scalar Glueball--Quarkonium Mixing and the Structure of the QCD Vacuum

TL;DR

This paper uses Ward identities and QCD vacuum condensates to estimate the mixing angle between scalar glueballs and quark-antiquark mesons, suggesting near-maximal mixing with strange quark pairs.

Contribution

It introduces a method based on Ward identities and vacuum condensates to quantify scalar glueball--quarkonium mixing, assuming dominance by a single scalar state.

Findings

Estimated mixing angle of approximately 36 degrees.

Indicates near-maximal mixing of glueball and strange quarkonium components.

Supports the single scalar state dominance hypothesis.

Abstract

We use Ward identities of broken scale invariance to infer the amount of scalar glueball--$\bar{q}q$ meson mixing from the ratio of quark and gluon condensates in the QCD vacuum. Assuming dominance by a single scalar state, as suggested by a phase-shift analysis, we find a mixing angle $\gamma \sim 36^{\circ}$, corresponding to near-maximal mixing of the glueball and $\bar{s}s$ components.