Abstract.
In this talk we will discuss cosmological and laboratory probes of dark states directly coupled to the photon. In a first scenario, the phenomenology of sub-GeV dark particles, directly coupled to electromagnetism through higher dimensional operators, is considered. The prospects of detecting such states at the intensity frontier are confronted with low-energy precision tests as well as with cosmological and astrophysical observables. In a second scenario, the perfect possibility that our Universe is filled with some form of dark radiation is explored. If the latter is composed of ultra-light dark photons, they may convert into ordinary photons and induce a variety of signatures. Among them is a modification of the cosmological 21cm signal. An explanation of tentative EDGES result is offered.
(The slides will be available here)