Majorana Dark Matter in a new B-L model

Abstract

We present a comprehensive study of Majorana dark matter in a U(1)B-L gauge extension of the standard model, where three exotic fermions with B-L charges as -4, -4, +5 are added to make the model free from the triangle gauge anomalies. The enriched scalar sector and the new heavy gauge boson Z′, associated with the U(1)B-L symmetry make the model advantageous to be explored in dual portal scenarios for the search of dark matter signal. Diagonalizing the exotic fermion mass matrix, we obtain the Majorana mass eigenstates, of which the lightest one plays the role of dark matter. Analyzing the effect of two mediators separately, the scalar portal channels give a viable parameter space consistent with relic density from PLANCK data and the direct detection limits from various experiments such as LUX, XENON1T and PandaX. While the Z′ mediated channels are constrained from relic abundance and LHC searches for Z′ in the dilepton channel. A massless physical Goldstone boson plays a key role in the scalar portal relic density. Finally, we briefly discuss the neutrino mass generation at one-loop level.