TOWARDS A UNIFIED STRING SUPERGRAVITY MODEL

We present a unified string supergravity model based on a string-derived SU (5) x U (1) model and a string-inspired supersymmetry breaking scenario triggered by the F-term of the universally present dilaton field. This model can be described by three parameters: m(t), tan beta, and m(g)approximately. We work out the predictions for all sparticle and Higgs masses and discuss the prospects for their detection at the Tevatron, LEPI, II, and HERA. We find that the cosmological neutralino relic density is always within current expectations (i.e., OMEGA(chi)h(0)2 less than or similar to 0.9). We also consider a more constrained version of this supersymmetry breaking scenario where the B-term is specified. In this case tan beta can be determined (tan beta almost-equal-to 1.4-1.6) and implies m(t) less than or similar to 155 GeV and m(h) less than or similar to 91 GeV. Thus, continuing Tevatron top-quark searches and LEPI, II Higgs searches could probe this restricted scenario completely.