English

A Lighter QCD Axion from Anarchy

High Energy Physics - Phenomenology 2023-08-15 v2

Abstract

We introduce the Anarchic Axion, a class of axion models which solves the Strong CP problem within current nEDM constraints with a lighter than usual QCD axion, thus populating new parameter space that ongoing and future experiments target. The Anarchic Axion is driven light by a soft breaking of the Peccei-Quinn symmetry, which also predicts a residual neutron electric dipole moment. We introduce a novel measure to quantify the tuning required for large deviations from the usual QCD axion band. In addition to motivating searches for unusually light axions, this work establishes a new target for axion effective field theory.

Keywords

Cite

@article{arxiv.2301.08760,
  title  = {A Lighter QCD Axion from Anarchy},
  author = {Fatemeh Elahi and Gilly Elor and Alexey Kivel and Julien Laux and Saereh Najjari and Felix Yu},
  journal= {arXiv preprint arXiv:2301.08760},
  year   = {2023}
}

Comments

5+2 pages. 3 figures. 1 table. v2: minor comments added, version published in Phys. Rev. D Letters

R2 v1 2026-06-28T08:16:36.332Z