A gauge model for right handed neutrinos as dark matter

We suggest a simple extension of the electroweak group, SU(2)(L) x U(1)(Y) x U(1)(B-L), where the breaking of U(1)(B-L) symmetry provides masses for right handed neutrinos, N, at an acceptable range for them to be Dark Matter (DM). We study the contributions to Moller and Bhabha scattering due to B - L neutral boson to constrain its gauge coupling. We analize N decay rates to determine the number of families that should be considered as DM candidates. The decoupling temperature between active and sterile neutrinos is also calculated.