Cosmological effects of Peccei-Quinn symmetry breaking on QCD axion dark matter

Abstract

We study cosmological effects of explicit Peccei-Quinn breaking on the QCD axion dark matter. We find that the axion abundance decreases or increases significantly depending on the initial position, even for a tiny Peccei-Quinn breaking that satisfies the experimental bound of the neutron electric dipole measurements. If the axion first starts to oscillate around a wrong vacuum and if it gets trapped there until the false vacuum disappears due to non-perturbative QCD effects, its abundance increases significantly and is independent of the decay constant $f_a$, as first pointed out in [JHEP 06 (2016) 150]. Thus, the axion produced by the trapping mechanism can explain dark matter even when the decay constant is close to the lower limit due to stellar cooling arguments. On the other hand, if the axion starts to oscillate about a potential minimum close to the low-energy vacuum, its abundance is significantly reduced because of the adiabatic suppression mechanism. This relaxes the upper limit of the axion window to large values of $f_a$. We also discuss how the axionic isocurvature perturbation is affected by the Peccei-Quinn breaking term, and show that it can be suppressed in both regimes. In particular, the isocurvature bound on the inflation scale is relaxed by many orders of magnitudes for $f_a\lesssim 10^{11}\mathrm{GeV}$ compared to the conventional scenario.

28 pages, 16 figures

References in corpus (17)

• Symmetries and Strings in Field Theory and Gravity
• The landscape of QCD axion models
• Measurement of the permanent electric dipole moment of the neutron
• Dielectric Haloscopes: A New Way to Detect Axion Dark Matter
• Update of axion CDM energy density
• Upper Limit on the QCD Axion Mass from Isolated Neutron Star Cooling
• Axion Quasiparticles for Axion Dark Matter Detection
• Axion mass limit from observations of the neutron star in Cassiopeia A
• Relaxing the Cosmological Moduli Problem by Low-scale Inflation
• Primordial Black Holes from QCD Axion Bubbles
• Testing clockwork axion with gravitational waves
• Stochastic Axion Dark Matter in Axion Landscape
• Axion/Hidden-Photon Dark Matter Conversion into Condensed Matter Axion
• Maximal axion misalignment from a minimal model
• The Stochastic Axiverse
• Trapping Effect for QCD Axion Dark Matter
• Constraints on axions from neutron star in HESS J1731-347

Cited by in corpus (4)

• Axion dark matter from first-order phase transition, and very high energy photons from GRB 221009A
• Resonant production of dark photons from axion without a large coupling
• Minimal solution to the axion isocurvature problem from a nonminimal coupling
• Flavour anomalies and dark matter assisted unification in $SO(10)$ GUT