Using Tau Polarization to probe the Stau Co-annihilation Region of   mSUGRA Model at LHC
  The mSUGRA model predicts the polarization of the tau coming from the stau to bino decay in the co-annihilation region to be +1. This can be exploited to extract this soft tau signal at LHC and also to measure the tiny mass differences between the stau and the bino LSP. Moreover this strategy will be applicable for a wider class of bino LSP models, where the lighter stau has a right component at least of similar size as the left. 
R. M. Godbole, Monoranjan Guchait, D. P. Roy