Implications of TeV flavor physics for the ΔI=1/2 rule and theBsemileptonic branching ratio

Abstract

Two of the outstanding discrepancies between weak interaction phenomenology and the standard model come in the large size of the \ensuremath{\Delta}I=1/2 enhancement in K decays and in the small value of the B semileptonic branching ratio. We argue that these discrepancies are naturally explained by chromomagnetic dipole operators arising from new physics at the TeV scale. These operators are closely connected to diagrams which contribute to the quark mass matrix, and we show how the proper enhancement of the hadronic decays of s and b quarks can be linked to a generation of particular Cabibbo-Kobayashi-Maskawa mixing angles or quark masses. We confirm our model-independent analysis with detailed consideration of supersymmetric models and of technicolor models with techniscalars. This picture has additional phenomenological predictions for the B system: The branching ratio of charmless nonleptonic B decays should be of order 20%, due to a larger rate for b\ensuremath{\rightarrow}sg, while there are no dangerous new contributions to b\ensuremath{\rightarrow}s\ensuremath{\gamma}. Sizable contributions to b\ensuremath{\rightarrow}d\ensuremath{\gamma} are a common feature of models incorporating this mechanism. In techniscalar models the ${\mathit{Zb}}_{\mathit{L}}$b${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathit{L}}$ coupling is enhanced, in association with sizable contributions to b\ensuremath{\rightarrow}s${\mathrm{\ensuremath{\mu}}}^{+}$${\mathrm{\ensuremath{\mu}}}^{\mathrm{\ensuremath{-}}}$.