Natural ranges of supersymmetric signals

The LEP2 experiments pose a serious naturalness problem for supersymmetric models. The problem is stronger in gauge mediation than in supergravity models. Particular scenarios, Like electroweak baryogenesis or gauge mediation with light messengers, are strongly disfavoured. Searching a theoretical reason that naturally explains why supersymmetry has not been found poses strong requests on model building. If instead an unlikely (p approximate to 5%) numerical accident has hidden supersymmetry to LEP2, we compute the naturalness distribution of values of allowed sparticle masses and supersymmetric loop effects. We find that b --> s gamma remains a very promising signal of minimal supersymmetry even if there is now a 20% (4%) probability that colored particles are heavier than 1 TeV (3 TeV). We study how much other effects are expected to be detectable. (C) 1999 Elsevier Science B.V. All rights reserved.