  We consider a supergravity (SUGRA) scenario, with universal scalar and
gaugino masses at high scale, with a right-chiral neutrino superfield included
in the spectrum. Such a scenario can have a lightest supersymmetric particle
(LSP) dominated by the right sneutrino and a stau as the next-to lightest
supersymmetric particle (NLSP). Since decays of all particles into the LSP are
suppressed by the neutrino Yukawa coupling, the signal of supersymmetry
consists in charged tracks of stable particles in the muon chamber. We
demonstrate how a neutralino decaying into a tau and the stau-NLSP can be fully
reconstructed over substantial areas in the SUGRA parameter space. We also
suggest event selection criteria for eliminating backgrounds, including
combinatorial ones, and use a new method for the extraction of the mass of the
stau-NLSP, using its three-momentum as obtained from the curvature of the
charged track.
