6,851 research outputs found

    On three-body B decays to charm

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    I briefly describe the use of the three-body decay modes B0D()D()0K+B^0 \to D^{(*)-} D^{(*)0} K^+ to investigate open issues in charmed meson spectroscopy, and of the time dependent B0(B0ˉ)(t)DD+π0B^0 (\bar {B^0}) (t) \to D^{-} D^{+} \pi^0 transitions for a measurement of cos(2β)\cos (2 \beta).Comment: LaTeX, 4 pages, 4 figs. Talk at 5th International Conference on Hyperons, Charm and Beauty Hadrons (BEACH 2002), Vancouver, Canada, 25-29 Jun 200

    B decays to excited charm mesons

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    We review several aspects of the phenomenology of P-wave qˉQ\bar q Q mesons: mass splittings, effective strong couplings and leptonic constants. We also describe a QCD sum rule determination to order αs\alpha_s of the form factor τ1/2(y)\tau_{1/2}(y) governing the semileptonic BB decays to the charm doublet with JP=(01/2+,11/2+)J^P=(0^+_{1/2},1^+_{1/2}).Comment: LaTex, 3 pages, 1 figure. Talk given at 3rd International Conference on Hyperons, Charm and Beauty Hadrons, Genoa, Italy, 30 Jun - 3 Jul 199

    The pion and proton mass in finite volume

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    We calculate the finite volume effects for the pion and nucleon mass. For the pion mass we present the results of a full two-loop calculation in chiral perturbation theory. The outcome shows that the resummed version of the Luscher formula we presented in an earlier work does indeed give an excellent approximation to the two-loop result. In view of this result we apply the same resummed formula to the nucleon mass. In the nucleon sector the extension of the chiral expansion to higher quark masses appears to be more problematic and it is therefore more difficult to make reliable predictions for the size of the finite volume effects. We present some preliminary numerical estimates.Comment: 10 pages, 3 figures, Talk given at the Workshop on Computational Hadron Physics, Cyprus, September 14-17, 200

    Finite volume effects for the pion mass at two loops

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    We evaluate the pion mass in finite volume to two loops within Chiral Perturbation Theory. The results are compared with a recently proposed extension of the asymptotic formula of Luscher. We find that contributions, which were neglected in the latter, are numerically very small at the two-loop level and conclude that for Mpi*L>2, L>2fm the finite volume effects in the meson sector are analytically well under control.Comment: 26 pages, 6 figure

    The quenched generating functional for hadronic weak interactions

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    The ultraviolet behaviour of the generating functional for hadronic weak interactions with ΔS=1,2|\Delta S| =1, 2 is investigated to one loop for a generic number of flavours and in the quenched approximation. New quenched chiral logarithms generated by the weak interactions can be accounted for via a redefinition of the weak mass term in the ΔS=±1\Delta S=\pm 1 weak effective Lagrangian at leading order. Finally, we illustrate how chiral logarithms are modified by the quenched approximation in KππK\to\pi\pi matrix elements with ΔI=1/2\Delta I=1/2 and 3/2.Comment: LATTICE98(matrixelement), 3 page

    Anomalous AVVAV^*V vertex in the soft-wall holographic model of QCD

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    We discuss the vertex function of two vector and one axial-vector operators in the soft-wall holographic model of QCD. When one of the two vector currents represents an on-shell soft photon, such a vertex is described by two structure functions wLw_L and wTw_T, which are usually calculated through triangular loop diagrams. We evaluate these functions in the soft-wall model of holographic QCD (HQCD) and compare the outcome to the QCD findings.Comment: 4 pages, contribution to conference "QCD 12", 16th International Conference in Quantum ChromoDynamics, 2nd-6th july 2012 (Montpellier - France

    The Riddle of Polarization in BVVB \to VV Transitions

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    Measurements of polarization fractions in BVVB \to VV transitions, with VV a light vector meson, show that the longitudinal amplitude dominates in B0ρ+ρB^0 \to \rho^+ \rho^-, B+ρ+ρ0B^+ \to \rho^+ \rho^0, and B+ρ0K+B^+ \to \rho^0 K^{*+} decays and not in the penguin induced decays B0ϕK0B^0 \to \phi K^{*0}, B+ϕK+B^+ \to \phi K^{*+}. We study the effect of rescattering mediated by charmed resonances, finding that in BϕKB \to \phi K^* it can be responsible of the suppression of the longitudinal amplitude. For the decay BρKB \to \rho K^* we find that the longitudinal fraction cannot be too large without invoking new effects.Comment: LaTex, 14 pages, 3 figure
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