8,710 research outputs found

    Charming penguin in nonleptonic B decays

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    In the study of two-body charmless B decays as a mean of looking for direct CP-violation and measuring the CKM mixing parameters in the Standard Model, the short-distance penguin contribution with its absorptive part generated by charm quark loop seems capable of producing sufficient BKπB \to K\pi decays rates, as obtained in factorization and QCD-improved factorization models. However there are also long-distance charming penguin contributions which also give rise to a strong phase due to the rescattering DDKπD^{*}D^{*} \to K\pi . In this talk, I would like to discuss \cite{Isola} a recent work on the long-distance charming penguin as a a different approach to the calculation of the penguin contributions in BKπB \to K\pi decays from charmed meson intermediate states. Using chiral effective Lagrangian for light and heavy mesons, corrected for hard pion and kaon momenta, we show that the charming-penguin contributions increase significantly the BKπB \to K\pi decays rates from its short-distance contributions, giving results in better agreement with experimental data.Comment: Talk given at the International Workshop on QCD: Theory and Experiment, Martina Franca, Italy, 16--20 June 2001, LaTex, 9 page

    CP-violating asymmetry in Bπ+πKB^- \to \pi^+ \pi^- K^- and BK+KKB^- \rarr K^+ K^- K^- decays

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    The recent Belle and Babar measurements of the branching ratios Bπ+πKB^- \to \pi^+ \pi^- K^- and BK+KKB^- \to K^+ K^- K^- and B±χc0K±B^\pm \to \chi_{c0} K^\pm have renewed interests in these decays as another mean to look for direct CP violation in B decays. In this talk, I would like to discuss a recent analysis of the CP violating asymmetry in the partial widths for the decays Bπ+πKB^- \to \pi^+ \pi^- K^- and BK+KKB^- \to K^+ K^- K^-, which results from the interference of the non resonant amplitude with the resonant amplitude B±χc0K±B^\pm \to \chi_{c0} K^\pm π+πK± \rarr\pi^+ \pi^- K^\pm and B±χc0K±B^\pm \to \chi_{c0} K^\pm K+KK± \to K^+ K^- K^\pm. For γ58o\gamma \simeq 58^o we predict that the partial width asymmetry could reach 10% for the Bπ+πKB^- \to \pi^+ \pi^- K^- decay and 16% for the BK+KKB^- \to K^+ K^- K^-decay.Comment: Talk given at the Quark Confinement and Hadron Spectrum V, Gargnano,Italy,10-14 September 2002, LaTeX,4 page

    Power corrections in charmless B decays

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    Power corrections seem to play an important role in charmless B decays as indicated by recent analysis using QCD Factorization. In this talk, I would like to report on a recent work on power corrections in charmless B decays. By using 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, it is shown in a transparent manner that power corrections in charmless B decays are probably large and that the B0Kρ+B^0 \to K^- \rho^+ decay could be explained with the annihilation term included. For ratios of direct CP asymmetries, QCD Factorisation with the annihilation terms included 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. In particular, the large measured value for Bπ±KB \to \pi^\pm K^\mp CP asymmetry implies naturally a corresponding large Bπ+πB \to \pi^+ \pi^- CP asymmetry as observed by Belle. Experimentally any significant deviation from this prediction or possibly the importance of long-distance rescattering effects.Comment: Talk given at the QCD Euroconference 2004, Montpellier 5-9 July 2004., LateX, 7 pages, 2 figure

    Relations for Direct CP asymmetries \\in BPPB\to \rm PP and BPVB\to \rm PV decays

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    The presence of additional strong phase from power corrections and other chirally enhanced terms makes it more difficult to predict direct CP asymmetries in two-body charmless B decays. In this talk, I would like to report on a recent work on QCD Factorisation and Power Corrections in Charmless B Decays. Using the measured branching ratios for BPVB\to \rm PV, it is shown that power corrections in charmless B decays are probably large, at least for penguin dominated PV\rm PV channels. Since the tree-penguin interference responsible for direct CP asymmetries in two-body charmless B decays are related by CKM factors and SU(3) symmetry, we find that, if power corrections other than the chirally enhanced power corrections and annihilation topology were negligible, QCD Factorisation 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, in agreement with the latest measurement from Belle. Similar relations are also given for direct CP asymmetries in BPVB\to\rm PV .Comment: Talk given at the QCD@Work 2005, Conversano, Bari, Italy, 16-20 June 2005, LateX, 7 pages, 2 figures, to appear in the Proceeding

    Non factorizable Effetcs in Bχc0KB \to \chi_{c0} K^- from Charmed Meson Rescattering

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    The Bχc0KB^{-} \to \chi_{c0} K^{-} decay which has no visible factorizable amplitude, could be induced by the Cabibbo-allowed, color-favored BDsD0B^{-} \to D_{s}D^{*0}, BDs0D0B^{-} \to D^{*0}_{s}D^{0} and BDsDB \to D_{s}^{*}D^{*} via the rescattering of these charmed mesons to χcoK\chi_{co} K^{-}. In this talk I would like to discuss a recent calculation \cite{Colangelo} of these effects for Bχc0KB^{-} \to \chi_{c0} K^{-} and BJ/ψKB^{-} \to J/\psi K^{-} decays. We find that charmed scattering effects seem capable of producing a large Bχc0KB^{-} \to \chi_{c0} K^{-} branching ratio measured by the Babar and Belle Collaboration and make a significant contribution to the BJ/ψKB^{-} \to J/\psi K^{-} branching ratios in agreement with experiments.Comment: Talk at the International Workshop on QCD: QCD@Work 2003 - Conversano (Italy) 14-18 June 2003 (eConf C030614), 4 pages LaTeX, 3 eps figures, revised version, 1 reference added, text unchange
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