Threshold corrections to mb and the b(b)over-bar→Hi0 production in CP-violating SUSY scenarios

The inclusion of supersymmetric threshold corrections to the b-quark mass has dramatic consequences in scenarios with large CP-mixing effects in the Higgs sector. In particular, when the phase of the combination M(g)u is similar to 180degrees +/- 30degrees, the lightest sbottom squark becomes tachyonic and, possibly, the b-quark Yukawa coupling nonperturbative for values of tan ranging from intermediate up to large or very large, depending on the size of arg(A(t)mu), arg(A(b)mu), and the details of the spectrum. For these scenarios, when allowed, as well as scenarios with different values of arg(M(g)mu), the cross sections for the production of the three neutral Higgs bosons through b-quark fusion have interesting dependences on arg(A(t)mu) and arg(A(b)mu), and the deviations induced by the m(b) corrections are rather large. In general, such production channel cannot be neglected with respect to the production through gluon fusion. For large CP-mixing effects, the lightest neutral Higgs boson can be mainly CP odd and the b-quark fusion becomes its main production mechanism. Searches at the Tevatron and the LHC can easily detect such a Higgs boson, or constrain the CP-violating scenarios that allow it. (C) 2004 Published by Elsevier B.V.