Scalar top quark as the next-to-lightest supersymmetric particle - art. no. 055004

We study phenomenologically the scenario in which the scalar top quark is l ighter than any other standard supersymmetric partner and also lighter than the top quark, so that it decays to the gravitino via (t) over tilde --> W (+)b (G) over tilde. In this case, scalar top quark events would seem to be Very difficult to separate from top quark pair production. However, we sho w that, even at a hadron collider, it is possible to distinguish these two reactions. We show also that the longitudinal polarization of the final Wgives insight into the scalar top quark and W-ino-Higgsino mixing parameter s.