Neutrino anomalies in a gauge mediated model with trilinearRviolation

Abstract

The structure of neutrino masses and mixing resulting from trilinear $R$ violating interactions is studied in the presence of the gauge mediated supersymmetry breaking. Neutrino masses arise in this model at tree level through the RG-induced vacuum expectation values of the sneutrinos and also through direct contribution at 1-loop. The relative importance of these contributions is determined by the values of the strong and weak coupling constants. In case of purely $\lambda'$ couplings, the tree contribution dominates over the 1-loop diagram. In this case, one simultaneously obtains atmospheric neutrino oscillations and quasi-vacuum oscillations of the solar neutrinos if all the $\l'$ couplings are assumed to be of similar magnitudes. If R parity violation arises from the trilinear $\l$ couplings, then the loop induced contribution dominates over the tree level. One cannot simultaneously explain the solar and atmospheric deficit in this case if all the $\l$ couplings are of similar magnitude. This however becomes possible with hierarchical $\l$ and we give a specific example of this.