Neutrino Mass Matrix in the Minimal Supergravity Model: Bi-large Mixing with Trilinear R-parity Violation

Abstract

We study the correlation between the neutrino oscillation and the production/decay of the lightest supersymmetric particle(LSP) in the context of the minimal supergravity model(mSUGRA) without R-parity. We show how the neutrino masses and mixing which are consistent with the recent neutrino data can be obtained in this model, and describe how to probe the model by observing the LSP decay at collider experiments. It is shown that the generic 1-loop contributions to neutrino masses are too small to account for the solar and atmospheric neutrino oscillations and thus some fine cancellation in tree-level contribution is required to severely constrain the viable parameter space. In most parameter space of mSUGRA, the neutralino or the stau is LSP. Examining both cases, we find that there is a simple correlation between the neutrino mixing angles and the LSP branching ratios in the small $\tanβ$ region so that the model can be clearly tested in the future colliders. In the large $\tanβ$ region, such a correlation is obscured by the large tau Yukawa contribution which makes it nontrivial to test the model.