Hidden Photon Dark Matter Interacting Via Axion-Like Particles

We investigate a scenario where the dark matter of the Universe is made from very light hidden photons transforming under a Z 2-symmetry. In contrast to the usual situation, kinetic mixing is forbidden by the symmetry and the dark photon interacts with the Standard Model photon only via an axion-like particle acting as a "messenger". Focusing on signatures involving the ordinary photon, our survey of the phenomenology includes limits from cosmological stability, CMB distortions, astrophysical energy loss, light-shining-through-walls experiments, helioscopes and solar X-ray observations. © 2021 IOP Publishing Ltd and Sissa Medialab.