Probing electroweak physics for allB→XMdecays in the endpoint region

Abstract

Using soft-collinear effective theory we describe at leading order in $1/{m}_{b}$ all the semi-inclusive hadronic $B\ensuremath{\rightarrow}XM$ decays near the endpoint, where an energetic light meson $M$ recoils against an inclusive jet $X$. Here we extend to the decays in which spectator quarks go into the jet $X$, and also include the decays involving $\ensuremath{\eta}$, ${\ensuremath{\eta}}^{\ensuremath{'}}$ mesons that receive additional contributions from gluonic operators. The predicted branching ratios and $CP$ asymmetries depend on fewer hadronic parameters than the corresponding two-body $B$ decays. This makes semi-inclusive hadronic $B\ensuremath{\rightarrow}XM$ decays a powerful probe of the potential nonperturbative nature of charming penguins as well as a useful probe of new physics effects in electroweak flavor changing transitions. A comparison with $B\ensuremath{\rightarrow}KX$ data from BABAR points to an enhanced charming penguin, albeit with large experimental errors.