Stau LSP Phenomenology: Two- versus Four-Body Decay Modes and Resonant   Single Slepton Production at the LHC as an Example
  We investigate B3 mSUGRA models, where the lightest scalar tau, stau_1, is the LSP. B3 models allow for lepton number and R-parity violation; the LSP can thus decay. We assume one non-zero B3 coupling lambda'_ijk at M_GUT, which generates further B3 couplings at M_Z. We study the RGEs and give numerical examples. The new couplings lead to additional stau_1 decays, providing distinct collider signatures. We classify the stau_1 decays and describe their dependence on the mSUGRA parameters. We exploit our results for single slepton production at the LHC. As an explicit numerical example, we investigate single smuon production, focussing on like-sign dimuons in the final state. Also considered are final states with three or four muons. 
H.K. Dreiner, S. Grab, and M.K. Trenkel