Right-handed neutrino dark matter with radiative neutrino mass in gauged B − L model

Abstract

We study the possibility of right-handed neutrino dark matter (DM) in gauged U (1) B−L × Z 2 extension of the standard model augmented by an additional scalar doublet, being odd under the Z 2 symmetry, to give rise to the scotogenic scenario of radiative neutrino masses. Due to lepton portal interactions, the right-handed neutrino DM can have additional co-annihilation channels apart from the usual annihilations through Z B−L which give rise to much more allowed mass of DM from relic abundance criteria, even away from the resonance region like M DM ≈ M Z B−L /2. This enlarged parameter space is found to be consistent with neutrino mass constraints while being sensitive to direct detection experiments of DM as well as rare decay experiments looking for charged lepton flavour violating decays like µ → eγ. Due to the possibility of the Z 2 odd scalar doublet being the next to lightest stable particle that can be sufficiently produced in colliders by virtue of its gauge interactions, one can have interesting signatures like displaced vertex or disappearing charged tracks provided that the mass splitting δM between DM and the next to lightest stable particle (NLSP) is small. In particular, we show that if δM < m τ = 1.77 GeV, then get large displaced vertex signature of NLSP while being consistent with neutrino mass, lepton flavour violation and observed relic density.

Complementarity between dark matter direct searches and CEνNS experiments in U(1)′ models

“…The Z channel also provides a tree-level spin-independent direct detection signature. It is well known that these two constraints (freeze-out relic density and direct detection bounds) are in tension for m χ < O(10 TeV) in U( 1) models [58][59][60][61][62][63][64][65]. For DM masses below O(10) GeV the direct detection bounds are much less stringent, due to poor detector sensitivity to nuclear recoils induced by the light dark matter.…”

Low scale U(1)X gauge symmetry as an origin of dark matter, neutrino mass and flavour anomalies

“…At the same time the additional chiral fermions required for anomaly cancelation could be made useful for neutrino mass generation as well. For similar construction of Abelian gauge extended models in the context of DM and neutrino mass generation, see [41][42][43][44][45][46][47][48][49] and references therein.…”

“…See[46,76] for scenarios where such contributions can be important. As we can see, the mediators of the DM interactions are the following: X ≡ Z , s2, H0, H ± and A2.…”

Connecting ANITA anomalous events to a nonthermal dark matter scenario

“…For example, the components of Z 2 odd scalar doublet can be produced at a significant rate at collider experiments like the large hadron collider (LHC) due to its electroweak gauge interactions. If it has tiny couplings with SM charged leptons like the ones we have considered in our work, we can have displaced vertex signatures at colliders, as discussed in a recent work [46]. Our model also has additional colored vector like Z 2 odd fermions which can also give rise to similar signatures at colliders.…”