Charming-penguin enhanced B decays

Abstract

Long-distance contributions of operators of the effective non-leptonic weak Hamiltonian containing charmed currents have been recently studied. Penguin-like contractions of these operators, denoted as charming penguins, have been shown to be relevant for several B decays into two pseudoscalar mesons. In particular, they are expected to give large enhancements to processes which would be otherwise Cabibbo suppressed. Their contributions easily lead to values of BR(B^+ \to K^0 π^+) and BR(B_d \to K^+ π^-) of about 1 \times 10^{-5}, as recently found by the CLEO collaboration. In this paper, we show that such large branching fractions cannot be obtained without charming penguins. This holds true irrespectively of the model used to compute the non-leptonic amplitudes and of the relevant parameters of the CKM mixing matrix. We use the experimental measurements of the B^+ \to K^0 π^+ and B_d \to K^+ π^- decay rates to constrain the charming-penguin amplitudes and to predict BRs for a large set of other two-body decay channels where their contributions are also important. These include several pseudoscalar-vector and vector-vector channels, such as B \to ρK and B \to ρK^*, which have not been measured yet.