Abstract
We discuss the possibility of realising a two-component dark matter (DM) scenario where the two DM candidates differ from each other by virtue of their production mechanism in the early universe. One of the DM candidates is thermally generated in a way similar to the weakly interacting massive particle (WIMP) paradigm where the DM abundance is governed by its freeze-out while the other candidate is produced only from non-thermal contributions similar to freeze-in mechanism. We discuss this in a minimal extension of the standard model where light neutrino masses arise radiatively in a way similar to the scotogenic models with DM particles going inside the loop. The lepton asymmetry is generated at the same time from WIMP DM annihilations as well as partially from the mother particle for non-thermal DM. This can be achieved while satisfying the relevant experimental bounds, and keeping the scale of leptogenesis or the thermal DM mass as low as 3 TeV, well within present experimental reach. In contrast to the TeV scale thermal DM mass, the non-thermal DM can be as low as a few keV, giving rise to the possibility of a sub-dominant warm dark matter (WDM) component that can have interesting consequences on structure formation. The model also has tantalizing prospects of being detected at ongoing direct detection experiments as well as the ones looking for charged lepton flavour violating process like $\mu \rightarrow e \gamma$.
Highlights
There have been irrefutable amount of evidences suggesting the presence of a mysterious, nonluminous, collisionless, and nonbaryonic form of matter in the present universe [1]
Since weakly interacting massive particle (WIMP) freeze-out and right handed neutrino decay are related to the generation of lepton asymmetry as well as FIMP generation respectively, one can see the yield in ΔL and FIMP by the epochs of WIMP freeze-out and right handed neutrino decay
It can be seen from these plots that the required asymmetry along with WIMP-FIMP relative abundance can be achieved simultaneously leading to a successful cogenesis
Summary
There have been irrefutable amount of evidences suggesting the presence of a mysterious, nonluminous, collisionless, and nonbaryonic form of matter in the present universe [1]. While the neutrinos in the SM come very close to satisfying these requirements, they have tiny abundance in the present universe Apart from that, they have a large free streaming length (FSL) due to their relativistic nature and give rise to hot dark matter (HDM), ruled out by observations. This has led to a plethora of beyond standard model (BSM) scenarios proposed by the particle physics community to account for dark matter in the universe. The so-called WIMPy baryogenesis [47,48,49] belongs to this category, where a dark matter particle freezes out to generate its own relic abundance and an asymmetry in the baryon sector is produced from DM annihilations.
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