Abstract

We study the predictions for mtop, tan ? and Vcb in a popular texture ansatz for the fermion mass matrices. We do this both for the Minimal Supersymmetric Standard Model (MSSM) and for the simplest model (MSSM-BRpV) where a bilinear R-parity violating term is added to the superpotential. We find that taking the experimental values for mtop and Vcb at 99% c.l. and the GUT relations hb = h? and V2cb = hc/ht within 5%, the large tan ? solution, characteristic in the MSSM with bottom-tau unification, becomes disallowed. In contrast, the corresponding allowed region for the MSSM-BRpV is slightly larger. We also find that important modifications occur if we relax the texture conditions at the GUT scale. For example, if the GUT relations are imposed at 40%, the large tan ? branch in the MSSM becomes fully allowed. In addition, in MSSM-BRpV the whole tan ?-mtop plane become allowed, finding unification at any value of tan ?. © 2000 Elsevier Science B.V. All rights reserved.