WIMPy leptogenesis in non-standard cosmologies

Abstract We study the possibility of generating baryon asymmetry universe from dark matter (DM) annihilations during non-standard cosmological epochs. Considering DM to be weakly interacting massive particle (WIMP) type, generation via leptogenesis route is studied where WIMP annihilation produces a non-zero lepton asymmetry. Adopting minimal physics model realise this along with light neutrino masses, we consider three different types cosmic history namely, (i) fast expanding universe, (ii) early domination and (iii) scalar-tensor theory gravity. By solving appropriate Boltzmann equations incorporating such history, find that allowed parameter space consistent relic observed gets enlarged lower mass in some scenarios. While lighter can face further scrutiny at direct search experiments, epochs offer complementary probes on their own.