English

Stacking the Deck: Gambling on a Light QCD Axion

High Energy Physics - Phenomenology 2025-10-21 v1

Abstract

We consider axions lighter than what their QCD couplings might otherwise suggest. Starting with a ZN\mathbb{Z}_N-axion, we introduce a small explicit ZN\mathbb{Z}_N symmetry-breaking coupling between the Standard Model Higgs boson and a reheaton. This small explicit breaking allows us to populate a large portion of the light axion mam_a-faf_a plane, removes the 1/N1/N tuning in the ZN\mathbb{Z}_N-axion, and explains why only our sector was reheated. Due to finite temperature effects, axions of this sort undergo either ``rigged" misalignment, where the axion misalignment angle is effectively π\pi regardless of its initial value; or ``shuffled" misalignment, where the initial angle is effectively randomized.

Keywords

Cite

@article{arxiv.2507.02049,
  title  = {Stacking the Deck: Gambling on a Light QCD Axion},
  author = {Abhishek Banerjee and Manuel A. Buen-Abad and Anson Hook},
  journal= {arXiv preprint arXiv:2507.02049},
  year   = {2025}
}

Comments

15 pages, 6 figures

R2 v1 2026-07-01T03:43:49.985Z