Cosmological abundance of the QCD axion coupled to hidden photons

Naoya Kitajima, Toyokazu Sekiguchi, Fuminobu Takahashi

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)

Abstract

We study the cosmological evolution of the QCD axion coupled to hidden photons. For a moderately strong coupling, the motion of the axion field leads to an explosive production of hidden photons by tachyonic instability. We use lattice simulations to evaluate the cosmological abundance of the QCD axion. In doing so, we incorporate the backreaction of the produced hidden photons on the axion dynamics, which becomes significant in the non-linear regime. We find that the axion abundance is suppressed by at most O(102) for the decay constant fa=1016GeV, compared to the case without the coupling. For a sufficiently large coupling, the motion of the QCD axion becomes strongly damped, and as a result, the axion abundance is enhanced. Our results show that the cosmological upper bound on the axion decay constant can be relaxed by a few hundred for a certain range of the coupling to hidden photons.

Original languageEnglish
Pages (from-to)684-687
Number of pages4
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume781
DOIs
Publication statusPublished - 2018 Jun 10

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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