Pseudo scalar dark matter in a generic U(1)X model

Abstract

We consider a U(1)X extension of the Standard Model (SM), where the spontaneous breaking of U(1)X gauge group results in a pseudo scalar particle which is the proposed candidate for dark matter. In the model, we introduce three right-handed neutrinos (RHNs) NRi and two extra scalars Φ, χ, which are SM gauge singlets but charged under U(1)X gauge group. Right-handed neutrinos are required to have the model anomaly free and explain the neutrino oscillation data. The heaviest scalar breaks the U(1)X gauge symmetry and the other extra scalar gives a pseudo scalar DM candidate. A pseudo scalar dark matter (DM) is an interesting candidate as it naturally evades the stringent direct detection bounds due to its coupling structure. We study the phenomenology of this pseudo-scalar DM while considering several theoretical and experimental constraints. We find that in our model, there is a feasible parameter space, which satisfies by the DM lifetime bound, relic and direct detection constraints while respecting the colliders and other bounds.