Glueballs from bound state equations

TL;DR

This paper reviews how to calculate glueballs, which are gluon-only bound states in quantum chromodynamics, using a functional approach, and discusses results for pure Yang-Mills theory demonstrating the method's stability and potential.

Contribution

It presents a self-contained functional framework for calculating glueballs in pure Yang-Mills theory, highlighting its consistency and complementarity to lattice methods.

Findings

Results show stable glueball spectra in pure Yang-Mills theory

Functional equations provide a continuum first-principles approach

Evidence supports the reliability of the method

Abstract

Glueballs are bound states in the spectrum of quantum chromodynamics which consist only of gluons. They belong to the group of exotic hadrons which are widely studied experimentally and theoretically. We summarize how to calculate glueballs in a functional framework and discuss results for pure Yang-Mills theory. Our setup is totally self-contained with the scale being the only external input. We enumerate a range of tests that provide evidence of the stability of the results. This illustrates the potential of functional equations as a continuum first-principles method complementary to lattice calculations.