B-Meson Observables in the Maximally CP-Violating MSSM with Minimal Flavour Violation

Additional sources of CP violation in the MSSM may affect B-meson mixings and decays, even in scenarios with minimal flavour violation (MFV). We formulate the maximally CPviolating and minimally flavour-violating (MCPMFV) variant of the MSSM, which has 19 parameters, including 6 phases that violate CP. We then develop a manifestly flavourcovariant effective Lagrangian formalism for calculating Higgs-mediated FCNC observables in the MSSM at large tanβ, and analyze within the MCPMFV framework FCNC and other processes involving B mesons. We include a new class of dominant subleading contributions due to non-decoupling 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. PACS numbers: 12.60.Jv, 13.20.He