Freeze-in baryogenesis and early matter domination

Abstract: The freeze-in mechanism has been shown to allow the simultaneous generation of cosmic dark matter and a viable matter-antimatter asymmetry in the universe. When the underlying interactions are described by higher-dimensional, non-renormalizable operators, the relevant freeze-in processes take place close to the highest considered cosmic temperatures. In this paper we study how the presence of a fluid that temporarily dominates the energy content of the early universe affects the predictions of this ``Ultraviolet Freeze-In Baryogenesis'' scenario. We find that this additional cosmic component has a significant impact on the predictions of concrete microscopic models, allowing for reheating temperatures which are much lower than those required in the simplest cosmological scenario. Moreover, we show that inflationary observables can constrain the parameter space of such models, once the latter are examined in conjunction with concrete models of inflation.