Basis independent study of Supersymmetry without R-parity and the tau   neutrino mass
  In the most general R-parity violating model, including both bilinear and trilinear terms, the sneutrino receives a vacuum expectation value. We investigate the constraints on this vev following a basis independent approach, highlighting the relations between the three most popular basis. We study the prediction for the tau neutrino mass which follows from the minimization of the scalar potential in a SUGRA model with universality of the soft parameters at the GUT scale. Finally we show that the tau neutrino mass controls the R-parity violating effects both in the fermionic and scalar sectors. 
Javier Ferrandis