224 research outputs found

    The Radiative rare decays BKγB\to K^{**}\gamma in the light-cone QCD sum rule approach

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    We predict contributions of higher KK-resonances to the radiative rare decays bsγb\to s\gamma, in the framework of the QCD sum rules on the light cone, which combines the traditional QCD sum rule method with the description of final state mesons in terms of the light-cone wave functions of increasing twist. Our calculations are restricted to the leading twist-two operators for K(892)K^*(892) and to the asymptotic wave function for the other KK^{**}-mesons. Using experimental data on the semileptonic τKντ\tau\to K^{**}\nu_{\tau} decays, we extract the corresponding decay constants for vector and axial-vector KK^{**}-mesons. Based on our estimate of the transition form factor F1K(892)(0)=0.32±0.06F_1^{K^*(892)}(0)=0.32 \pm 0.06 and the K2(1430)K_2^*(1430) decay constant fK2(1430)=(160±20)MeVf_{K_2^*(1430)}=(160\pm 20) MeV, we find good agreement with experimental results. The two largest fractions of the inclusive bsγb\to s\gamma branching ratio are found to be (10.0±4.0)(10.0\pm 4.0)% for BK(892)γB\to K^*(892) \gamma and (5.0±2.0)(5.0\pm 2.0)% for BK2(1430)γB\to K_2^*(1430)\gamma decays. We also compare our results with the existing theoretical predictions.Comment: 29 pages, 20 figures, to be submitted to European Physical Journal

    Analysis of the BK2(1430),a2(1320),f2(1270)B \to K^*_2(1430), a_2(1320), f_2(1270) form-factors with light-cone QCD sum rules

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    In this article, we study the BK2(1430)B \to K^*_2(1430), a2(1320)a_2(1320), f2(1270)f_2(1270) form-factors with the light-cone QCD sum rules, where the BB-meson light-cone distribution amplitudes are used. In calculations, we observe that the line-shapes of the BB-meson light-cone distribution amplitude ϕ+(ω)\phi_+(\omega) have significant impacts on the values of the form-factors, and expect to obtain severe constraints on the parameters of the BB-meson light-cone distribution amplitudes from the experimental data in the future.Comment: 19 pages, 6 figures, slight revisio

    Branching Ratio and CP-asymmetry for B-> 1^{1}P_{1}gamma decays

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    We calculate the branching ratios for B_{d}^{0}->(b_{1},h_{1})gamma at next-to-leading order (NLO) of alpha_{s} where b_{1} and h_{1} are the corresponding radially excited axial vector mesons of rho and omega respectively. Using the SU(3)symmetry for the form factor, the branching ratio for B_{d}^{0}->(b_{1},h_{1})gamma is expressed in terms of the branching ratio of the B_{d}^{0}-> K_{1}gamma and it is found to be B(B_{d}^{0}->b_{1}gamma)=0.71* 10^{-6} and B(B_{d}^{0}-> h_{1}gamma) =0.74*10^{-6}. We also calculate direct CP asymmetry for these decays and find, in confirmity with the observations made in the literature, that the hard spectator contributions significantely reduces the asymmetry arising from the vertex corrections alone. The value of CP-asymmetry is 10% and is negative like rho and omega in the Standard Model.Comment: 10 pages, 2 figure

    Phenomenological discussion of BPVB\to P V decays in QCD improved factorization approach

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    Trying a global fit of the experimental branching ratios and CP-asymmetries of the charmless BPVB\to PV decays according to QCD factorization, we find it impossible to reach a satisfactory agreement, the confidence level (CL) of the best fit is smaller than .1 %. This failure reflects the difficulty to accommodate several large experimental branching ratios of the strange channels. Furthermore, experiment was not able to exclude a large direct CP asymmetry in Bˉ0ρ+π\bar {B}^0\to\rho^+ \pi^-, which is predicted very small by QCD factorization. Proposing a fit with QCD factorization complemented by a charming-penguin inspired model we reach a best fit which is not excluded by experiment (CL of about 8 %) but is not fully convincing. These negative results must be tempered by the remark that some of the experimental data used are recent and might still evolve significantly.Comment: 8 pages, 2 figures (requires epsfig, psfrag),talk presented at the XXXVIIIth Rencontres de Moriond: Electroweak Interactions and Unified Theories,Les Arcs, France, March 15-22, 2003. To be published in the Proceeding

    Use of ERTS data for a multidisciplinary analysis of Michigan resources

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    There are no author-identified significant results in this report

    CP Violation in B -> pi+ pi- and the Unitarity Triangle

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    We analyze the extraction of weak phases from CP violation in Bπ+πB\to\pi^+\pi^- decays. We propose to determine the unitarity triangle (ρˉ,ηˉ)(\bar\rho,\bar\eta) by combining the information on mixing induced CP violation in Bπ+πB\to\pi^+\pi^-, SS, with the precision observable sin2β\sin 2\beta obtained from the CP asymmetry in BψKSB\to\psi K_S. It is then possible to write down exact analytical expressions for ρˉ\bar\rho and ηˉ\bar\eta as simple functions of the observables SS and sin2β\sin 2\beta, and of the penguin parameters rr and ϕ\phi. As an application clean lower bounds on ηˉ\bar\eta and 1ρˉ1-\bar\rho can be derived as functions of SS and sin2β\sin 2\beta, essentially without hadronic uncertainty. Computing rr and ϕ\phi within QCD factorization yields precise determinations of ρˉ\bar\rho and ηˉ\bar\eta since the dependence on rr and ϕ\phi is rather weak. It is emphasized that the sensitivity to the phase ϕ\phi enters only at second order and is extremely small for moderate values of this phase, predicted in the heavy-quark limit. Transparent analytical formulas are further given and discussed for the parameter CC of direct CP violation in Bπ+πB\to\pi^+\pi^-. We also discuss alternative ways to analyze SS and CC that can be useful if new physics affects BdB_d--Bˉd\bar B_d mixing. Predictions and uncertainties for rr and ϕ\phi in QCD factorization are examined in detail. It is pointed out that a simultaneous expansion in 1/mb1/m_b and 1/N leads to interesting simplifications. At first order infrared divergences are absent, while the most important effects are retained. Independent experimental tests of the factorization framework are briefly discussed.Comment: 26 pages, 7 figure

    Implications of the first observation of BK1γB\to K_1\gamma

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    Implications of the recent new measurements of BK1γB\to K_1\gamma by Belle are examined. It is shown that the new branching ratio \calB(B\to K_1(1270)\gamma) requires very large form factor compared to the theoretically predicted one. This is an opposite case to BKγB\to K^*\gamma where theory expected larger branching ratio. Possible origins of the discrepancy are discussed.Comment: 4 pages, 3 figure

    Exclusive B-meson Rare Decays and General Relations of Form Factors in Effective Field Theory of Heavy Quarks

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    B meson rare decays (BK(K)llˉB\to K(K^{*})l\bar l and BKγB\to K^*\gamma) are analyzed in the framework of effective field theory of heavy quarks. The semileptonic and penguin type form factors for these decays are calculated by using the light cone sum rules method at the leading order of 1/mQ1/m_Q expansion. Four exact relations between the two types of form factors are obtained at the leading order of 1/mQ1/m_Q expansion. Of particular, the relations are found to hold for whole momentum transfer region. We also investigate the validity of the relations resulted from the large energy effective theory based on the general relations obtained in the present approach. The branching ratios of the rare decays are presented and their potential importance for extracting the CKM matrix elements and probing new physics is emphasized.Comment: 23 pages, Revtex, 32 figures, published version with the errors of numerical results caused by the computer program are correcte

    Bd^0(t)->pi^+pi^- and Bs^0(t)-> K^+ K^- Decays: A Tool to Measure New-Physics Parameters

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    If physics beyond the standard model is present in B decays, experimental measurements seem to suggest that it principally affects those processes with significant b->s penguin amplitudes. It was recently argued that, in general, such new-physics (NP) effects can be parametrized in terms of a single NP amplitude A^q and phase \Phi_q, for q=u,d,s,c. In this paper, we show that the study of the decays Bs(t) -> K^+ K^- and Bd(t) -> \pi^+\pi^- allows one to measure the NP parameters A^u and \Phi_u. We examine the implications for this method of the latest experimental results on these decays. If NP is found in Bs(t) -> K^+ K^-, it can be partially identified through measurements of Bs(t)-> K^0 \bar K^0.Comment: 12 pages, 2 figures, LaTeX. Changed reference