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

New gauge bosons at the MeV scale with tiny gauge couplings (so-called darkphotons) can be responsible for the freeze-in production of dark matter andprovide a clear target for present and future experiments. We study the effectsof thermal mixing between dark photons and Standard Model gauge bosons and ofthe resulting plasmon decays on dark matter production before and after theelectroweak phase transition. In the parameter regions preferred by theobserved dark matter relic abundance, the dark photon is sufficientlylong-lived to be probed with fixed-target experiments and light enough toinduce direct detection signals. Indeed, current limits from XENON1T alreadyconstrain Dirac fermion dark matter in the GeV to TeV range produced via thefreeze-in mechanism. We illustrate our findings for the case of a $U(1)_{B-L}$gauge extension and discuss possible generalisations.

Probing the freeze-in mechanism in dark matter models with $U(1)^\prime$ gauge extensions