Analytic study of dark photon and gravitational wave production from axion
Abstract
Axion-like fields heavier than about 10−27 eV are expected to oscillate in the radiation dominated epoch when the Hubble parameter drops below their mass. Considering the Chern-Simons coupling with a dark gauge boson, large amount of dark photons are produced during a short time interval through tachyonic resonance instability. The produced dark photons then source gravitational tensor modes leading to chiral gravitational waves. Through this process, one can indirectly probe a large parameter space of coupled axion-dark photon models. In this work we first find an analytic expression for the number density of the dark photons produced during the tachyonic resonance regime. Second, by using the saddle point approximation we find an analytic expression for the gravitational wave spectrum in terms of the mass, coupling and misalignment angle. Our analytic results can be used for the observational analysis of these types of scenarios.
- Publication:
-
Journal of High Energy Physics
- Pub Date:
- May 2021
- DOI:
- 10.1007/JHEP05(2021)043
- arXiv:
- arXiv:2007.08148
- Bibcode:
- 2021JHEP...05..043S
- Keywords:
-
- Cosmology of Theories beyond the SM;
- Beyond Standard Model;
- High Energy Physics - Phenomenology;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- General Relativity and Quantum Cosmology;
- High Energy Physics - Theory
- E-Print:
- 29+15 pages, 10 figures, presentation is improved, comparison with numerical results are added, matches with the published version