81 research outputs found

    Determination of the CP violating weak phase γ\gamma from the Decays BDπB \to D \pi

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    We propose a new method to extract the CP violating weak phase γ\gamma (the phase of VubV_{ub}^*) in the CKM paradigm of the Standard Model, using BD0πfπB^- \rightarrow D^0 \pi^- \rightarrow f \pi^- and BDˉ0πfπB^- \rightarrow \bar D^0 \pi^- \rightarrow f \pi^- decays, where ff are final states such as K+πK^+ \pi^-, K+ρK^+ \rho^-, KππK \pi\pi, {\it etc.} We also study the experimental feasibility of our new method. With possibility of new phases in the CKM matrix, we re-examine some of the previously proposed methods to determine γ\gamma, and find that it would be in principle possible to identify γ\gamma and a new phase angle θ\theta separately.Comment: 12 pages, 1 figure, LaTex; the version to be published in European Physical Journal

    Charmless hadronic B decays and the recent CLEO data

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    In the light of recent experimental data from the CLEO Collaboration we study, the decays of B mesons to a pair of pseudoscalar (P) mesons, and a vector (V) meson and a pseudoscalar meson, in the framework of factorization. In order to obtain the best fit for the recent CLEO data, we critically examine the values of several input parameters to which the predictions are sensitive. These input parameters are the form factors, the strange quark mass, ξ1/Nc\xi \equiv 1/ N_c (N_c is the effective number of color), the CKM matrix elements and in particular, the weak phase γ\gamma. It is possible to give a satisfactory account of the recent experimental results in BPPB \to PP and VP decays, with constrained values of a \emph{single} ξ\xi. We identify the decay modes in which CP asymmetries are expected to be large.Comment: 24 pages, 11 figures, LaTex; Version to appear in Phys. Rev.

    Constraints on a New Light Spin-One Particle from Rare b -> s Transitions

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    The anomalously large like-sign dimuon charge asymmetry in semileptonic b-hadron decays recently measured by the D0 Collaboration may be hinting at the presence of CP-violating new physics in the mixing of B_s mesons. It has been suggested that the effect of a nonstandard spin-1 particle lighter than the b quark with flavor-changing couplings to b and s quarks can reproduce the D0 result within its one-sigma range. Here we explore the possibility that the new particle also couples to charged leptons l=e,mu and thus contributes to rare b -> s processes involving the leptons. We consider in particular constraints on its couplings from existing experimental data on the inclusive B -> X_s l^+ l^- and exclusive B -> K^{(*)} l^+ l^- decays, as well as the anomalous magnetic moments of the leptons. We find that there is parameter space of the particle that is allowed by the current data. Future measurements of these B transitions and rare decays of the B_s meson, such as B_s -> (phi,eta,eta') l^+ l^- and B_s -> l^+ l^-, at LHCb and next-generation B factories can probe its presence or couplings more stringently.Comment: 19 pages, 5 figure

    An extension of tribimaximal lepton mixing

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    Harrison, Perkins and Scott have proposed simple charged lepton and neutrino mass matrices that lead to the tribimaximal mixing UTBMU_{\rm TBM}. We consider in this work an extension of the mass matrices so that the leptonic mixing matrix becomes UPMNS=VLUTBMWU_{\rm PMNS}=V_L^{\ell\dagger}U_{\rm TBM}W, where VLV_L^\ell is a unitary matrix needed to diagonalize the charged lepton mass matrix and WW measures the deviation of the neutrino mixing matrix from the bimaximal form. Hence, corrections to UTBMU_{\rm TBM} arise from both charged lepton and neutrino sectors. Following our previous work to assume a Qin-Ma-like parametrization VQMV_{\rm QM} for the charged lepton mixing matrix VLV_L^\ell in which the {\it CP}-odd phase is approximately maximal, we study the phenomenological implications in two different scenarios: VL=VQMV_L^\ell=V_{\rm QM}^\dagger and VL=VQMV_L^\ell=V_{\rm QM}. We find that the latter is more preferable, though both scenarios are consistent with the data within 3σ3\sigma ranges. The predicted reactor neutrino mixing angle θ13\theta_{13} in both scenarios is consistent with the recent T2K and MINOS data. The leptonic {\it CP} violation characterized by the Jarlskog invariant JCPJ_{\rm CP} is generally of order 10210^{-2}.Comment: 20 pages and 8 figures, Accepted in Phys.Review

    Charmless Non-Leptonic B Decays and R-parity Violating Supersymmetry

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    We examine the charmless hadronic B decay modes in the context of R-parity violating (\rpv) supersymmetry. We try to explain the large branching ratio (compared to the Standard Model (SM) prediction) of the decay B±ηK±B^{\pm}\to \eta' K^{\pm}. There exist data for other observed η()\eta^{(\prime)} modes and among these modes, the decay B0ηK0B^{0}\to \eta K^{*0} is also found to be large compared to the SM prediction. We investigate all these modes and find that only two pairs of \rpv coupling can satisfy the requirements without affecting the other B\ra PP and B\ra VP decay modes barring the decay B\ra\phi K. From this analysis, we determine the preferred values of the \rpv couplings and the effective number of color NcN_c. We also calculate the CP asymmetry for the observed decay modes affected by these new couplings.Comment: 14 pages, 7 figures; revtex; version published in Phys. Lett.