Resummation of tan β-enhanced supersymmetric loop corrections beyond the decoupling limit

We study the Minimal Supersymmetric Standard Model with Minimal Flavour Violation for the case of a large parameter tan beta and arbitrary values of the supersymmetric mass parameters. We derive several resummation formulae for tan beta-enhanced loop corrections, which were previously only known in the limit of supersymmetric masses far above the electroweak scale. Studying first the renormalisation-scheme dependence of the resummation formula for the bottom Yukawa coupling, we clarify the use of the sbottom mixing angle in the supersymmetric loop factor Delta(b). As a new feature, we find tan beta-enhanced loop-induced flavour-changing neutral current (FCNC) couplings of gluinos and neutralinos which in turn give rise to new effects in the renormalisation of the Cabibbo-Kobayashi-Maskawa matrix and in FCNC processes of B mesons. For the chromomagnetic Wilson coefficient C-8, these gluino-squark loops can be of the same size as the known chargino-squark contribution. We discuss the phenomenological consequences for the mixing-induced CP asymmetry in B-d -> phi K-S. We further quote formulae for B-s -> mu(+)mu(-) and B-s - (B) over bar (s) mixing valid beyond the decoupling limit and find a new contribution affecting the phase of the B-s-(B) over bar (s) mixing amplitude. Our resummed tan beta-enhanced effects are cast into Feynman rules permitting an easy implementation in automatic calculations.