Glueball Axion-Like Particles

TL;DR

This paper introduces a new class of composite glueball axion-like particles (GALPs) arising from dark Yang-Mills sectors, which could serve as viable dark matter candidates and are testable through astrophysical observations.

Contribution

It explores the phenomenology of glueball ALPs, including their effective interactions with photons and gluons, extending the concept of ALPs to a composite dark sector.

Findings

Glueball ALPs can span a wide mass range from sub-eV to Planck scale.

Effective interactions of GALPs with photons and nucleons are similar to standard ALP phenomenology.

GALPs are viable dark matter candidates detectable via astrophysical and cosmological probes.

Abstract

Dark Yang-Mills sectors that confine to form stable composite states, known as glueballs, have been traditionally proposed as a potential explanation for cosmological Dark Matter (DM). Earlier studies have established viability of the lightest scalar glueball as a possible DM candidate. In this work, we explore a whole class of effective composite sectors in the confined Yang-Mills regime featuring an additional pseudoscalar glueball state. We also investigate the role of effective interactions of the dark glueball sector with the visible sectors via higher-dimensional operators primarily focusing on dimension-8 couplings of glueballs to photons and gluons. We stress the remarkable similarities between the phenomenology of such glueball effective theories and Standard Model extensions featuring Axion-Like Particles (ALPs). Hence, one deals with a new class of composite Glueball ALPs (or GALPs) coupled to photons and/or nucleons in a wide mass range, from sub-eV to the Planck scale, yielding viable DM candidates that can be probed by astrophysical and cosmological observations.