B-meson observables in the maximally CP-violating MSSM with minimal flavor violation

Additional sources of CP violation in the MSSM may affect B-meson mixings and decays, even in scenarios with minimal flavor violation (MFV). We formulate the maximally CP-violating and minimally flavor-violating (MCPMFV) variant of the MSSM, which has 19 parameters, including 6 phases that violate CP. We then develop a manifestly flavor-covariant effective Lagrangian formalism for calculating Higgs-mediated flavor-changing-neutral-current (FCNC) observables in the MSSM at large tan β, and analyze within the MCPMFV framework FCNC and other processes involving B mesons. We include a new class of dominant subleading contributions due to nondecoupling effects of the third-generation quarks. We present illustrative numerical results that include effects of the CP-odd MCPMFV parameters on Higgs and sparticle masses, the Bs and Bd mass differences, and on the decays Bs→μ+μ-, Bu→τν, and b→sγ. We use these results to derive illustrative constraints on the MCPMFV parameters imposed by D0, CDF, Belle, and BABAR measurements of B mesons, demonstrating how a potentially observable contribution to the CP asymmetry in the b→sγ decay may arise in the MSSM with MCPMFV. © 2007 The American Physical Society.