Dark matter assisted Dirac leptogenesis and neutrino mass

Abstract

We propose an extension of the standard model with U (1)B−L × Z2 symmetry. In this model by assuming that the neutrinos are Dirac (i.e. B − L is an exact symmetry), we found a simultaneous solution for non zero neutrino masses and dark matter content of the universe. The observed baryon asymmetry of the universe is also explained using Dirac Leptogenesis, which is assisted by a dark sector, gauged under a U (1)D symmetry. The latter symmetry of the dark sector is broken at a TeV scale and thereby giving mass to a neutral gauge boson ZD. The standard model Z-boson mixes with the gauge boson ZD at one loop level and paves a way to detect the dark matter through spin independent elastic scattering at terrestrial laboratories.

Freeze-in Dirac neutrinogenesis: thermal leptonic CP asymmetry

“…Such feeble couplings, in spite of their nonaesthetic nature, are generically present, if the sub-eV Dirac neutrino masses are generated by the Higgs-like mechanism with a vacuum expectation value (VEV) chosen around the electroweak scale. On the other hand, such a mechanism of neutrino mass generation is often criticized on account of naturalness, and dynamical explanations of the smallness of neutrino masses are, therefore, more biased by enlarging the Yukawa space and/or introducing sufficiently heavy particles, which have also been considered in explicit realizations of the DN [5][6][7][8][9].…”

“…As an alternative to most DN applications in which the lepton-number asymmetry is generated by non-thermal heavy particle decays [3,[5][6][7][8][9], we have considered the case where the asymmetry is accumulated via the freeze-in production of right-handed neutrinos from thermal scalar decay.…”

“…In the typical versions of DN mechanism [3,[5][6][7][8][9], the lepton-number asymmetry is generated by heavy particle decays with a non-thermal distribution. In addition, in order to discuss the loop correction for nonzero kinetic phase (or the absorptive part of the decay amplitude), one usually focuses on the new particle sector, which is also the general case in seesaw-based leptogenesis [10][11][12], while the contribution from wavefunction correction in the lepton-doublet sector has not yet been considered to the best of our knowledge.…”

Dirac Leptogenesis in assistance of Dark Matter and Neutrino Mass

“…The presence of X-particles and their interactions the mass matrix of X can be replaced with new mass matrix and after diagonalising the new mass matrix we get new mass eigenstates ξ ± 1 and ξ ± 2 . For further details [6]. The CP-violation arises via the interference of tree level and one loop self energy correction diagrams and the asymmetry ε L in the visible sector can be calculated.…”

Linking pseudo-Dirac dark matter to radiative neutrino masses in a singlet-doublet scenario

“…[38] (subsequently in Ref. [39]) demonstrated that the inclusion of a small Majorana mass term for the singlet fermion in the Lagrangian splits the DM eigenstate into two nearly degenerate Majorana states with a tiny mass difference. In the small Majorana mass limit, the splitting does not make any difference to the relic abundance analysis; however, it makes a vital portal to the direct detection of the pseudo-Dirac DM candidate [38].…”