b to d d s bar transition and constraints on new physics in B^- decays
  The b to d d s bar transition gives extremely small branching ratios within the standard model, thus providing an appropriate ground for testing new physics. Using renormalization group technique we determine the Wilson coefficients and the mixing of the operators which contribute to the b to d d s bar transition. We consider contributions to this decay mode from the supersymmetric standard model with and without R-parity, as well as from a model with an additional neutral Z' gauge boson. Using Belle and BaBar upper bounds for the B^- to pi^- pi^- K^+ branching ratio we constrain contributions of these new physics scenarios. Then we calculate branching ratios for two- and three-body nonleptonic B^- meson decays driven by the b to d d s transition, which might be experimentally accessible. 
Svjetlana Fajfer, Jernej Kamenik, Nejc Kosnik