Low Mass Pseudoscalar Dark Matter in an Extended B - L Model

Abstract

We study an extended B-L model, which has in its structure four neutral scalars. In this model, a representative set of parameters enable us to conclude that one of these scalars is a promising candidate for low-mass dark matter. We introduce an Z_2 symmetry, which ensure the stability of the dark matter. The dominant annihilation process will be through $s$-channel exchange of a scalar in $b\overline{b}$. So, this is also a Higgs portal dark matter model, but the Higgs decay to dark matter is suppressed and meets the constraints from invisible decays of Higgs boson. The model is also in agreement with the constraints established by XENON100, CoGeNT and CDMS experiments, maching the relic abundance and the cross section with nucleon.