Bi-large neutrino mixing from bilinear R-parity violation with non-universality

We investigate how the bi-large mixing required by the recent neutrino data can be accommodated in the supersymmetric standard model allowing bilinear R-parity violation and non-universal soft terms. In this scheme, the tree-level contribution and the so-called Grossman–Haber one-loop diagrams are two major sources of the neutrino mass matrix. The relative size of these two contributions falls into the right range to generate the atmospheric and solar neutrino mass hierarchy. On the other hand, the bi-large mixing is typically obtained by a mild tuning of input parameters to arrange a partial cancellation among various contributions.