In scenarios of the Minimal Supersymmetric Standard Model where the gravitino is the LSP and the Stop is the NLSP, the Stop could have a long life-time, which makes it a quasi-stable particle that requires special strategies for its search at hadron colliders. We calculate the lifetime for the stop decay in different regions of parameter space where the different N-body modes are open, namely: stop→ top+gravitino (2-body), stop → b+W +gravitino (3-body) and stop → b+l+nu+gravitino (4-body). The calculation presented here are simplified thanks to the implementation of appropriate helicity methods, suited to deal with the massive case. We work within the conext of the Phenomenological version of the MSSM. Implications for collider physics and cosmology are also discussed at the end of this talk.
|Parallel Session||Supersymmetry: Models, Phenomenology and Experimental Results|