The charged-Higgs-boson contributions to the Wilson coefficients C 7 and C8, relevant for the decay B → X sγ, are discussed in supersymmetric models at large tanβ. These contributions receive two-loop O(α, tanβ) corrections by squark-gluino subloops, which are possibly large and nondecoupling in the limit of heavy superpartners. In previous studies, the relevant two-loop Feynman integrals were approximated by using an effective two-Higgs-doublet lagrangian. However, this approximation is theoretically justified only when the typical supersymmetric scale MSUSY is sufficiently larger than the electroweak scale mweak ∼ (mw, mt) and the mass of the chargcd-Higgs boson mH±. Here, we evaluate these two-loop integrals exactly and compare the results with the existing, approximated ones. We then examine the validity of this approximation beyond the region where it has been derived, i.e. for mH ≳ MSUSY and/or MSUSY ∼ mweak.
|Journal||Journal of the Korean Physical Society|
|Issue number||2 SUPPL.|
|Publication status||Published - 2004 Nov 1|
- B meson decay
ASJC Scopus subject areas
- Physics and Astronomy(all)