Gorghetto, Marco, Hardy, Edward ORCID: 0000-0003-3263-6575 and Nicolaescu, Horia
(2021)
Observing invisible axions with gravitational waves.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, 2021 (6).
034-034.
Text
2101.11007v1.pdf - Submitted version Download (9MB) | Preview |
Abstract
If the Peccei-Quinn symmetry associated to an axion has ever been restored after inflation, axion strings inevitably produce a contribution to the stochastic gravitational wave background. Combining effective field theory analysis with numerical simulations, we show that the resulting gravitational wave spectrum has logarithmic deviations from a scale invariant form with an amplitude that is significantly enhanced at low frequencies. As a result, a single ultralight axion-like particle with a decay constant larger than $10^{14}~{\rm GeV}$ and any mass between $10^{-18}~{\rm eV}$ and $10^{-28}~{\rm eV}$ leads to an observable gravitational wave spectrum and is compatible with constraints on the post-inflationary scenario from dark matter overproduction, isocurvature and dark radiation. Since the spectrum extends over a wide range of frequencies, the resulting signal could be detected by multiple experiments. We describe straightforward ways in which the Peccei-Quinn symmetry can be restored after inflation for such decay constants. We also comment on the recent possible NANOgrav signal in light of our results.
Item Type: | Article |
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Additional Information: | 39 pages + appendices |
Uncontrolled Keywords: | axions, Cosmic strings, domain walls, monopoles, gravitational waves / theory, cosmology of theories beyond the SM |
Depositing User: | Symplectic Admin |
Date Deposited: | 11 Feb 2021 11:12 |
Last Modified: | 18 Jan 2023 23:00 |
DOI: | 10.1088/1475-7516/2021/06/034 |
Open Access URL: | https://iopscience.iop.org/article/10.1088/1475-75... |
Related URLs: | |
URI: | https://livrepository.liverpool.ac.uk/id/eprint/3115485 |