New strategies for new physics search inB→K*νν̄,B→Kνν̄ andB→Xsνν̄ decays

Abstract

The rare decay B ? K*? is regarded as one of the important channels in B physics as it allows a transparent study of Z penguin and other electroweak penguin effects in New Physics (NP) scenarios in the absence of dipole operator contributions and Higgs (scalar) penguin contributions that are often more important than Z contributions in B ? K*?+?? and Bs ? ?+?? decays. We present a new analysis of B ? K*? with improved form factors and of the decays B ? K? and B ? Xs? in the SM and in a number of NP scenarios like the general MSSM, general scenarios with modified Z/Z' penguins and in a singlet scalar extension of the SM. We also summarize the results in the Littlest Higgs model with T-parity and a Randall-Sundrum (RS) model with custodial protection of left-handed Zdij couplings. Our SM prediction BR(B ? K*?) = (6.8+1.0?1.1) ? 10?6 turns out to be significantly lower than the ones present in the literature. Our improved calculation BR(B ? Xs?) = (2.7?0.2) ? 10?5 in the SM avoids the normalization to the BR(B ? Xcee) and, with less than 10% total uncertainty, is the most accurate to date. The results for the SM and NP scenarios can be transparently summarized in a (,?) plane analogous to the known (,) plane with a non-vanishing ? signalling this time not CP violation but the presence of new right-handed down-quark flavour violating couplings which can be ideally probed by the decays in question. Measuring the three branching ratios and one additional polarization observable in B ? K*? allows to overconstrain the resulting point in the (,?) plane with (,?) = (1,0) corresponding to the SM. We point out that the correlations of these three channels with the rare decays K+ ? ?+?, KL ? ?0?, B ? Xs?+?? and Bs ? ?+?? offer powerful tests of New Physics with new right-handed couplings and non-MFV interactions.