Abstract: An angular analysis of the B-0 -> K*(0) (-> K+pi(-))mu(+)mu(-) decay is presented. The dataset corresponds to an integrated luminosity of 3.0 fb(-1) of pp collision data collected at the LHCb experiment. The complete angular information from the decay is used to determine CP-averaged observables and CP asymmetries, taking account of possible contamination from decays with the K+pi(-) system in an S-wave configuration. The angular observables and their correlations are reported in bins of q(2), the invariant mass squared of the dimuon system. The observables are determined both from an unbinned maximum likelihood fit and by using the principal moments of the angular distribution. In addition, by fitting for q(2)-dependent decay amplitudes in the region 1.1 < q(2) < 6.0 GeV2/(c)4, the zero-crossing points of several angular observables are computed. A global fit is performed to the complete set of CP-averaged observables obtained from the maximum likelihood fit. This fit indicates differences with predictions based on the Standard Model at the level of 3.4 standard deviations. These differences could be explained by contributions from physics beyond the Standard Model, or by an unexpectedly large hadronic effect that is not accounted for in the Standard Model predictions.

Abstract: As a top-factory, the LHC is performing a direct study of top-quark anomalous FCNC couplings, which are, however, correlated closely with the rare B- and K-meson decays. In this paper, we study the effects of anomalous tqZ (with q = u, c) couplings in the rare decays B-s,B-d -> mu(+)mu(-), B -> X-s nu(nu) over bar, B -> K(*)nu(nu) over bar, K+ -> pi(+)nu(nu) over bar, and K-L -> pi(0)nu(nu) over bar. With the up-to-date experimental bounds on the branching ratios of these channels, constraints on the left-handed anomalous couplings X-ct(L), and X-ut(L) are derived, respectively. With these low-energy constraints taken into account, we find that, for real couplings X-ct(L) and X-ut(L), the indirect upper bounds on B(t -> qZ) are much lower than that from the D0 collaboration, but are still compatible with the 5 sigma discovery potential of ATLAS with an integrated luminosity of 10 fb(-1). With refined measurements to be available at the LHCb, the future super-B factories, the NA62 at CERN, and the KOTO at J-PARC, closer correlations between the t -> qZ and the rare B- and K-meson decays are expected in the near future, which will be helpful for the searches of thu e top-quark FCNC decays at the LHC.

Abstract: A search for the lepton-flavour violating decays B-(s)(0) -> e(+/-)mu(-/+) and B-(s)(0) -> e(+/-)mu(-/+) performed based on a sample of proton-proton collision data corresponding to an integrated luminosity of 3 fb(-1), collected with the LHCb experiment at centre-of-mass energies of 7 and 8TeV. The observed yields are consistent with the background-only hypothesis. Upper limits on the branching fraction of the B-(s)(0) -> e(+/-)mu(-/+) decays are evaluated both in the hypotheses of an amplitude completely dominated by the heavy eigenstate and by the light eigenstate. The results are B(B-s(0) -> e(+/-)mu(-/+)) < 6.3 (5.4) x 10(-9) and B(B-s(0) -> e(+/-)mu(-/+)) < 7.2(6.0) x 10(-9) at 95% (90%) confidence level, respectively. The upper limit on the branching fraction of the B-0 -> e(+/-)mu(-/+) decay is also evaluated, obtaining B(B-0 -> e(+/-)mu(-/+)) < 1.3 (1.0) x 10(-9) at 95% (90%) confidence level. These are the strongest limits on these decays to date.