Very light asymmetric dark matter

Abstract

Very light dark matter is usually taken to consist of uncharged bosons such\nas axion-like particles or dark photons. Here, we consider the prospect of very\nlight, possibly even sub-eV dark matter carrying a net charge that is\n(approximately) conserved. By making use of the Affleck-Dine mechanism for its\nproduction, we show that a sizable fraction of the energy density can be stored\nin the asymmetric component. We furthermore argue that there exist regions of\nparameter space where the energy density contained in symmetric\nparticle-antiparticle pairs without net charge can to some degree be depleted\nby considering couplings to additional fields. Finally, we make an initial\nforay into the phenomenology of this scenario by considering the possibility\nthat dark matter is coupled to the visible sector via the Higgs portal.\n