Spontaneous baryogenesis from extremely light asymmetric dark matter

Abstract

We present a mechanism where a particle asymmetry in one sector is used to generate an asymmetry in another sector. The two sectors are not coupled through particle number violating interactions and are not required to be in thermal contact with each other. When this mechanism is applied to baryogenesis in asymmetric dark matter models, we find that the dark matter particles can be extremely light, e.g. much lighter than an eV, and that in some cases there is no need to annihilate away the symmetric component of dark matter. We discuss a concrete realization of the mechanism with signals in direct detection, at the LHC, at B-factories or future beam dump experiments.

Spontaneous baryogenesis from asymmetric inflaton

“…If there are current-current interactions between the inflaton number and the B−L symmetry, the excited CPodd inflaton quanta induces an effective chemical potential of the B − L number. This leads to the spontaneous baryogenesis if the B − L number is broken in thermal plasma [8][9][10][11], because the inflaton asymmetry biases the B − L number. As for the B − L breaking, one may introduce dimension five interactions for the neutrino mass, motivated by the seesaw mechanism [12].…”

“…In Ref [11],. a four-Fermi interaction between DM and B − L currents withG F ∼ 1/(10 TeV) 2 and the associated spontaneous baryogenesis were studied in an asymmetric dark matter model.…”

Asymmetric dark matter and effective number of neutrinos

“…In an ADM model [2], there is a common mechanism that might give rise to the baryon asymmetry as well as the ADM asymmetry and we obtain Ω ADM /Ω b ≃ (η χ /η b )(m χ /m p ), where Ω ADM , η b , η χ , m χ and m p are the ADM abundance, the baryon asymmetry, the ADM asymmetry, the ADM mass and the proton mass, respectively. From this relation, the natural scale for ADM is around 5 GeV, however, mass of the ADM can be as low as a few keV in some models [3,4]. Moreover, the light non-asymmetric DM (we call it symmetric DM or simply DM), such as MeV to GeV DM, remains an elusive blind spot in the current underground searches [5].…”

Particle asymmetries from quantum statistics

“…The use of a CP T -violating background is similar in spirit to models of spontaneous baryogenesis [21,22] 1 . Another example of this effect is the use of J 0 D to generate a CP violating coupling in the Lagrangian much in the same way that the Higgs vacuum expectation value allows for one to write a SU (2) W breaking Lagrangian coupling [23].…”