Tau Lepton Mixing with Charginos and its Effects on Chargino Searches at   e+e- Colliders
  In bilinear R-Parity violating models where a term \epsilon_3L_3H_2 is introduced in the superpotential, the tau lepton can mix with charginos. We show that this mixing is fully compatible with LEP1 precision measurements of the Z\tau\tau and W\tau\nu_\tau couplings even for large values of \epsilon_3 and of the induced vacuum expectation value v_3 of the tau-sneutrino. The single production of charginos at e+e- colliders is possible in this case and we present numerical values of the cross-section at LEP1, LEP2 and an NLC. We find maximum values of 10 pb at LEP1 and 1 fb at NLC, while the corresponding values at LEP2 are too small to observe. 
A.G. Akeroyd, Marco A. Diaz and Jose W.F. Valle (Valencia)