Analytical study of non-universality of the soft terms in the MSSM

We obtain general analytical forms for the solutions of the one-loop renorm alization group equations in the top/bottom/tau sector of the MSSM. These s olutions are valid for any value of tan beta as well as any non-universal i nitial conditions for the soft SUSY breaking parameters and non-unification of the Yukawa couplings. We establish analytically a generic screening eff ect of nonuniversality, in the vicinity of the infrared quasi fixed point, which allows to determine sector-wise a hierarchy of sensitivity to initial conditions. We give also various numerical illustrations of this effect aw ay from the quasi fixed point and assess the sensitivity of the Higgs and s fermion spectra to the non-universality of the various soft breaking sector s. As a by-product, a typical anomaly-mediated non-universality of the gaug ino sector would have marginal influence on the scalar spectrum. (C) 2000 E lsevier Science B.V. All rights reserved.