The minimal cosmological standard model

Abstract

We propose a novel minimal scenario which simultaneously addresses the following theoretical/cosmological/phenomenological puzzles: (i) the origin of scales, (ii) primordial inflation, (iii) matter-antimatter asymmetry, (iv) tiny neutrino masses, (v) dark matter, and (vi) the strong CP-problem. Exact scale-symmetry was assumed. A global $U(1)_{\rm PQ}$-symmetry was also assumed but only in the matter sector. The novelty of the scenario is the introduction of an explicit $U(1)_{\rm PQ}$-breaking term in the gravity sector only. Such a term does not disturb the axion solution whereas naturally realizes an axi-majoron hybrid inflation which allows a natural realization of Affleck-Dine mechanism for generating Peccei-Quinn number asymmetry. The asymmetry can be transferred to the visible sector via the right-handed neutrino portal through non-thermal decay and thermal processes, even without the presence of a CP-violating phase in the matter sector. Dark matter and dark radiation are obtained by cold and hot components of axi-majorons, respectively.