TeV Scale Leptogenesis in B-L Model with Alternative Cosmologies
  In TeV scale B-L extension of the standard model with inverse seesaw, the Yukawa coupling of right-handed neutrinos can be of order one. This implies that the out of equilibrium condition for leptogenesis within standard cosmology is not satisfied. We provide two scenarios for overcoming this problem and generating the desired value of the baryon asymmetry of the Universe. The first scenario is based on extra-dimensional braneworld effects that modify the Friedman equation. We show that in this case the value of the baryon asymmetry of the Universe constrains the five-dimensional Planck mass to be of order O(100) TeV. In the second scenario a non-thermal right-handed neutrino produced by the decay of inflaton is assumed. We emphasize that in this case, it is possible to generate the required baryon asymmetry of the Universe for TeV scale right-handed neutrinos. 
W. Abdallah, D. Delepine, S. Khalil
hep-ph