Supersymmetric $U(1)_{Y^{\prime}}\otimes U(1)_{B-L}$ extension of the   standard model
  We build a supersymmetric version with $SU(3)_C\otimes SU(2)_L\otimes U(1)_{Y^\prime}\otimes U(1)_{B-L}$ gauge symmetry, where $Y^\prime$ is a new charge and $B$ and $L$ are the usual baryonic and leptonic numbers. The model has three right-handed neutrinos with identical $B-L$ charges, and can accommodate all fermion masses at the tree level. In particular, the type-I seesaw mechanism is implemented for the generation of the active neutrino masses. We obtain the mass spectra of all sectors and for the scalar one we also give the flat directions allowed by the model. 
J. C. Montero and V. Pleitez and M. C. Rodriguez and B. L.   S\'anchez-Vega
hep-ph