Constrained minimal supersymmetric standard model with generalized Yukawa quasiunification

Abstract

We analyze the constrained minimal supersymmetric standard model with mu>0 supplemented by a generalized `asymptotic' Yukawa coupling quasi-unification condition, which allows an acceptable b-quark mass. We impose constraints from the cold dark matter abundance in the universe, B physics, and the mass of the lightest neutral CP-even Higgs boson. We find that, in contrast to previous results obtained for a more restrictive Yukawa quasi-unification condition, the lightest neutralino can act as a cold dark matter candidate in a relatively wide parameter range. In this range, the lightest neutralino relic abundance is drastically reduced mainly by stau-antistau coannihilations and, thus, the upper bound on this abundance from cold dark matter considerations becomes compatible with the recent data on the branching ratio of B_s --> mu^+mu^-. Also, masses for the lightest neutral CP-even Higgs boson about (125-126) GeV, favored by LHC, can be easily accommodated. The mass of the lightest neutralino, though, comes out large (~1 TeV).