Rare hadronic B decays in the MSSM and in other models of new physics

In this thesis we study several aspects of new physics (NP) in rare hadronic B decays: First we analyse tan(beta)-enhanced corrections in the Minimal Supersymmetric Standard Model (MSSM). We generalise the known resummation formulas beyond the decoupling limit and study novel effects in couplings involving genuine SUSY particles. In the second part of the thesis we discuss the possibility of probing NP in electroweak penguins via the purely isospin-violating decays B_s->phi,pi(rho).