Abstract
An extension of the Standard Model with Majorana singlet fermions in the 1–100 GeV range can explain the light neutrino masses and give rise to a baryon asymmetry at freeze-in of the heavy states, via their CP-violating oscillations. In this paper we consider extending this scenario to also explain dark matter. We find that a very weakly coupled B-L gauge boson, an invisible QCD axion model, and the singlet majoron model can simultaneously account for dark matter and the baryon asymmetry.
Highlights
The standard model (SM) of particle physics needs to be extended to explain neutrino masses, the missing gravitating matter (DM) and the observed matter-antimatter asymmetry in the universe.Some of the most minimal extensions of the SM include new fermions, namely two or three sterile Majorana neutrinos, which can account for the tiny neutrino masses, through the seesaw mechanism [1,2,3,4], and explain the observed matter-antimatter asymmetry through leptogenesis [5]
The sterile neutrinos relevant for leptogenesis are the heavier ones, m N2,3, with masses in the 1–100 GeV, and we focus on the scenario where mV ≤ 2m N2,3
The possibility to generate the baryon asymmetry in this model a la Fukugita-Yanagida for very heavy neutrinos m N ∼ fa was recognized in the original proposal [46] and further elaborated in [98]
Summary
The standard model (SM) of particle physics needs to be extended to explain neutrino masses, the missing gravitating matter (DM) and the observed matter-antimatter asymmetry in the universe. Some of the most minimal extensions of the SM include new fermions, namely two or three sterile Majorana neutrinos (singlets under the full gauge group), which can account for the tiny neutrino masses, through the seesaw mechanism [1,2,3,4], and explain the observed matter-antimatter asymmetry through leptogenesis [5]. For Majorana neutrinos in the 1–100 GeV range, it has been shown by Akhmedov, Rubakov and Smirnov (ARS) [8] and refined by Asaka and Shaposhnikov (AS) [9] that a different mechanism of leptogenesis is at work In this case the asymmetries are produced at freezein of the sterile states via their CP-violating oscillations.
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