TTP09-26 Resummation of tan-beta-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 C8, 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 <-> anti-B mixing valid beyond the
 decoupling limit and find a new contribution affecting the phase of
 the B <-> anti-B mixing amplitude. Our resummed tan-beta-enhanced effects are
 cast into Feynman rules permitting an easy implementation in automatic
 calculations.