English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A variety of supergravity and string models involve hidden sectors where thehidden sectors may couple feebly with the visible sectors via a variety ofportals. While the coupling of the hidden sector to the visible sector isfeeble its coupling to the inflaton is largely unknown. It could couple feeblyor with the same strength as the visible sector which would result in either acold or a hot hidden sector at the end of reheating. These two possibilitiescould lead to significantly different outcomes for observables. We investigatethe thermal evolution of the two sectors in a cosmologically consistent hiddensector dark matter model where the hidden sector and the visible sector arethermally coupled. Within this framework we analyze several phenomena toillustrate their dependence on the initial conditions. These include theallowed parameter space of models, dark matter relic density, proton-darkmatter cross section, effective massless neutrino species at BBN time,self-interacting dark matter cross-section, where self-interaction occurs viaexchange of dark photon, and Sommerfeld enhancement. Finally fits to thevelocity dependence of dark matter cross sections from galaxy scales to thescale of galaxy clusters is given. The analysis indicates significant effectsof the initial conditions on the observables listed above. The analysis iscarried out within the framework where dark matter is constituted of darkfermions and the mediation between the visible and the hidden sector occurs viathe exchange of dark photons. The techniques discussed here may haveapplications for a wider class of hidden sector models using differentmediations between the visible and the hidden sectors to explore the impact ofBig Bang initial conditions on observable physics.

Big Bang initial conditions and self-interacting hidden dark matter