837 research outputs found

    Study of pure annihilation type decays BDsKB \to D_s^{*} K

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    In this work, we calculate the rare decays B0DsK+B^0 \to D_s^{*-} K^+ and B+Ds+Kˉ0B^+ \to D_s^{*+} \bar{K}^0 in perturbative QCD approach with Sudakov resummation. We give the branching ratio of 10510^{-5} for B0DsK+B^0 \to D_s^{*-}K^+, which will be tested soon in BB factories. The decay B+Ds+Kˉ0B^+ \to D_s^{*+} \bar{K}^0 has a very small branching ratio at O(108){\cal O}(10^{-8}), due to the suppression from CKM matrix elements VubVcd|V_{ub}^* V_{cd}|. It may be sensitive to new physics contributions.Comment: 14 pages, 1 figur

    Reparametrization invariance of B decay amplitudes and implications for new physics searches in B decays

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    When studying B decays within the Standard Model, it is customary to use the unitarity of the CKM matrix in order to write the decay amplitudes in terms of only two of the three weak phases which appear in the various diagrams. Occasionally, it is mentioned that those two weak phases can be used in order to describe any decay amplitude, even beyond the Standard Model. Here we point out that, when describing a generic decay amplitude, the two weak phases can be chosen completely at will, and we study the behavior of the decay amplitudes under changes in the two weak phases chosen as a basis. Of course, physical observables cannot depend on such reparametrizations. This has an impact in discussions of the SM and in attempts to parametrize new physics effects in the decay amplitudes. We illustrate these issues by looking at B --> psi K_S and the isospin analysis in B --> pi pi.Comment: 16 pages, RevTe

    Helicity conservation and factorization-suppressed charmless B decays

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    Toward the goal of extracting the weak angle alpha, the decay B^0/B^0-bar to a_0^{+/-}pi^{-/+} was recently measured. The decay B^0 to a_0^+pi^- is not only forbidden in the factorization limit of the tree interaction, but also strongly suppressed for the penguin interaction if short-distance QCD dominates. This makes extraction of alpha very difficult from a^{+/-}\pi^{-/+}. We examine the simlar factorization-suppressed decays, in particular, B^0\to b_1^+pi^-. The prospect of obtaining alpha is even less promising with b_1^{+/-}pi^{-/+}. To probe how well the short-distance dominance works, we emphasize importance of testing helicity conservation in the charmless B decays with spins.Comment: The version to appear in Phys. Rev. D after minor alteration

    Perturbative QCD analysis of BϕKB \to \phi K^* decays

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    We study the first observed charmless BVVB\to VV modes, the BϕKB\to\phi K^* decays, in perturbative QCD formalism. The obtained branching ratios B(BϕK)15×106B(B\to\phi K^*)\sim 15 \times 10^{-6} are larger than 9×106\sim 9\times 10^{-6} from QCD factorization. The comparison of the predicted magnitudes and phases of the different helicity amplitudes, and branching ratios with experimental data can test the power counting rules, the evaluation of annihilation contributions, and the mechanism of dynamical penguin enhancement in perturbative QCD, respectively.Comment: 14 pages, 2 tables, brief disscussion on hard sacle added, version to appear in PR

    Electric Dipole Moments in the Generic Supersymmetric Standard Model

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    The generic supersymmetric standard model is a model built from a supersymmetrized standard model field spectrum the gauge symmetries only. The popular minimal supersymmetric standard model differs from the generic version in having R-parity imposed by hand. We review an efficient formulation of the model and some of the recently obtained interesting phenomenological features, focusing on one-loop contributions to fermion electric dipole moments.Comment: 1+7 pages Revtex 3 figures incoporated; talk at NANP'0

    B meson light-cone wavefunctions in the heavy quark limit

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    We present a systematic study of the B meson light-cone wavefunctions in QCD in the heavy-quark limit. We construct model-independent formulae for the light-cone wavefunctions in terms of independent dynamical degrees of freedom, which exactly satisfy the QCD equations of motion and constraints from heavy-quark symmetry. The results demonstrate novel behaviors of longitudinal as well as transverse momentum distribution in the B mesons.Comment: 5 pages LaTeX, 1 style file. Talk presented at RADCOR/Loops and Legs 2002, Kloster Banz, Germany, September 8-13, 200

    Power Corrections in Charmless B Decays

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    In this paper, we focus on the role of power corrections in QCD factorization(QCDF) method in charmless two-body nonleptonic BB meson decays. We use the ratio of the branching fraction of B+π+K0B^+ \to \pi^+ K^{\ast 0} to that of B0πρ+B^0 \to \pi^- \rho^+, for which the theoretical uncertainties are greatly reduced, to show clearly that the power corrections in charmless B decays are probably large. With other similar ratios considered, for example, for the B0Kρ+B^0 \to K^- \rho^+ decay, it is very likely that, among various sources of power corrections, annihilation topology plays an indispensable role at least for penguin dominated PV\rm PV channels. We also consider some selective ratios of direct CP asymmetries. Among these, we find that, if power corrections other than the chirally enhanced power corrections and annihilation topology were negligible, QCDF would predict the direct CP asymmetry of Bπ+πB \to \pi^+ \pi^- to be about 3 times larger than that of Bπ±KB \to \pi^\pm K^\mp, with opposite sign. Experimentally any significant deviation from this prediction would suggest either new physics or possibly the importance of long-distance rescattering effects.Comment: references and note added, to appear in Phys. Rev.

    Possible Large Direct CP Violations in Charmless B-Decays

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    We discuss the perturbative QCD approach for the exclusive two body B-meson decays to light mesons. We briefly review its ingredients and some important theoretical issues on factorization approach. We show numerical results which are compatible with present experimantal data for the charmless B-meson decays. Specailly we predict the possibility of large direct CP violation effects in B0π+πB^0 \to \pi^{+}\pi^{-} (23±7(23\pm7 %) and B0K+πB^0\to K^{+}\pi^{-} (17±5(-17\pm5%). In the last section we investigate two methods to determine the weak phases ϕ2\phi_2 and ϕ3\phi_3 from Bππ,KπB \to \pi\pi,K\pi processes. We obtain bounds on ϕ2\phi_2 and ϕ3\phi_3 from present experimental measurements.Comment: 18 pages, latex, 8 figures and 8 tables, typos corrected and added more tables and references. Presented at the 3rd workshop on Higher Luminosity B Factory, 6-7 August 2002, Kanagawa, Japan; Submitted to Phys. Rev.

    Study of color suppressed modes B0Dˉ()0η()B^0 \to \bar D^{(*)0} \eta^{(\prime)}

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    The color suppressed modes B0Dˉ()0η()B^0 \to \bar D^{(*)0} \eta^{(\prime)} are analyzed in perturbative QCD approach. We find that the dominant contribution is from the non-factorizable diagrams. The branching ratios calculated in our approach for B0Dˉ()0ηB^0 \to \bar D^{(*)0} \eta agree with current experiments. By neglecting the gluonic contribution, we predict the branching ratios of B0Dˉ()0ηB^0 \to \bar D^{(*)0} \eta' are at the comparable size of B0Dˉ()0π0B^0 \to \bar D^{(*)0} \pi^0, but smaller than that of B0Dˉ()0ηB^0 \to \bar D^{(*)0} \eta .Comment: revtex, 5 pages, axodraw.st

    Branching ratios of B+D()+K()0B^+ \to D^{(*)+}K^{(*)0} decays in perturbative QCD approach

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    We study the rare decays B+D()+K()0B^+ \to D^{(*)+}K^{(*)0}, which can occur only via annihilation type diagrams in the standard model. We calculate all of the four modes, BPP,VP,PV,VVB \to PP, VP, PV, VV, in the framework of perturbative QCD approach and give the branching ratios of the order about 10610^{-6}.Comment: 18 pages, 1 figure, Revte
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