We reconsider thermal production of axions in the early universe, including axion couplings to all Standard Model (SM) particles. Concerning the axion coupling to gluons, we find that thermal effects enhance the axion production rate by a factor of few with respect to previous computations performed in the limit of small strong gauge coupling. Furthermore, we find that the top Yukawa coupling induces a much larger axion production rate, unless the axion couples to SM particles only via anomalies.
@article{arxiv.1310.6982,
title = {Thermal axion production},
author = {Alberto Salvio and Alessandro Strumia and Wei Xue},
journal= {arXiv preprint arXiv:1310.6982},
year = {2016}
}
Comments
16 pages, 5 figures. v3: we thank Daniel Green and Benjamin Wallisch for having pointed out a numerical error in the electroweak gauge contribution in fig. 5, which has been corrected