Dark sectors as an approach to BSM searches. From terrestrial experiments to astrophysical ones.

Neutrino masses, dark matter and the baryon asymmetry of the Universe call for new physics beyond the Standard Model. In recent years, low scale extensions of the Standard Model, the so-called dark sectors, have received significant attention: they postulate the existence of new particles and interactions below the electroweak scale and they communicate with the visible sector via feebly couplings, called portals. The main strength of this approach is that we can get a rich phenomenology from just a few added dark parameters of the theory. Their existence is highly motivated by observed anomalies in a vast range of experiments. We study one particular dark model in detail, the Three Portal model, though we also consider other kinds of realizations of dark sectors. We first present the current status of dark sector parameters. Then, we explain the role of dark sectors in one particular neutrino anomaly: MiniBooNE's low energy excess. We particularly study how a dark photon and one or two heavy neutral leptons from the Three Portal model could explain the anomalous events in MiniBooNE and perform a fitting of the model. Furthermore, we consider this model in hot white dwarfs, so that constraints could be set on the parameter space of the dark photon.