Baryogenesis via dark matter-induced symmetry breaking in the early Universe

Abstract

We put forward a new proposal for generating the baryon asymmetry of the universe by making use of the dynamics of a U(1) scalar field coupled to dark matter. High dark matter densities cause the U(1) symmetry to break spontaneously so that the field acquires a large vacuum expectation value. The symmetry is restored when the density redshifts below a critical value, resulting in the coherent oscillation of the scalar field. A net B−L number can be generated either via baryon number-conserving couplings to the standard model or through small symmetry-violating operators and the subsequent decay of the scalar condensate.