Heavy QCD axion model in light of pulsar timing arrays
M. Ahmadvand, Ligong Bian, Soroush Shakeri
Abstract
Recently, pulsar timing array experiments reported the observation of a stochastic gravitational wave background in the nanohertz range frequency band. We show that such a signal can be originated from a cosmological first-order phase transition (PT) within a well-motivated heavy (visible) QCD axion model. Considering the Peccei-Quinn symmetry breaking at the TeV scale in the scenario, we find a supercooled PT, in the parameter space of the model, prolonging the PT with the reheating temperature at the GeV scale.
Topics & Concepts
AxionPhysicsPulsarParticle physicsQuantum chromodynamicsNuclear physicsAstronomyDark matterDark Matter and Cosmic PhenomenaCosmology and Gravitation TheoriesAtomic and Subatomic Physics Research