Hot versus Cold Hidden Sectors and Their Effects on Thermal Relics
A variety of possibilities exist for dark matter aside from WIMPS, such as hidden sector dark matter. We
discuss the synchronous thermal evolution of visible and hidden sectors and show that the density of
thermal relics can change O(100%) and ∆Neff by a factor of up to 105 depending on whether the hidden
sector was hot or cold at the reheat temperature. It is also shown that the approximation of using separate
entropy conservation for the visible and hidden sectors is invalid even for a very feeble coupling between
This work is licensed under a Creative Commons Attribution 4.0 International License.
Letters in High Energy Physics (LHEP) is an open access journal published by Andromeda Publishing and Education Services. The articles in LHEP are distributed according to the terms of the creative commons license CC-BY 4.0. Under the terms of this license, copyright is retained by the author while use, distribution and reproduction in any medium are permitted provided proper credit is given to original authors and sources.
Terms of Submission
By submitting an article for publication in LHEP, the submitting author asserts that:
1. The article presents original contributions by the author(s) which have not been published previously in a peer-reviewed medium and are not subject to copyright protection.
2. The co-authors of the article, if any, as well as any institution whose approval is required, agree to the publication of the article in LHEP.