291 research outputs found

    Chiral sum rules to second order in quark mass

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    A new calculation of the isospin and hypercharge axialvector current propagators (ΔA33μν(q2)\Delta_{A33}^{\mu\nu}(q^2) and ΔA88μν(q2)\Delta_{A88}^{\mu\nu}(q^2)) to two loops in SU(3) x SU(3) chiral perturbation theory is used to derive chiral spectral function sum rules valid to second order in the light quark masses. Explicit forms are given for the three-pion isospin axialvector spectral functions at low energy and application of the sum rules to the determination of counterterms of the chiral lagrangian is discussed.Comment: Figures extended down to threshold; Eq. (19) expressed in simplified for

    The Color-Octet intrinsic charm in η\eta^\prime and BηXB\to \eta^\prime X decays

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    Color-octet mechanism for the decay B\to \eta^\prime X is proposed to explain the large branching ratio of Br(B\to \eta^\prime X)\sim 1\times 10^{-3} recently announced by CLEO. We argue that the inclusive \eta^\prime production in B decays may dominantly come from the Cabbibo favored b\to (\bar c c)_8s process where \bar c c pair is in a color-octet configuration, and followed by the nonperturbative transition (\bar c c)_8\to \eta^\prime X. The color-octet intrinsic charm component in the higher Fock states of \eta^\prime is crucial and is induced by the strong coupling of \eta^\prime to gluons via QCD axial anomaly.Comment: 9 pages, RevTex, 1 PS figur

    Accounting for Slow J/psi from B Decay

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    A slow J/psi excess exists in the inclusive B -> J/psi+X spectrum, and is indicative of some hadronic effect. From color octet nature of c cbar pair in b-> c cbar s decay, one such possibility would be B -> J/psi+ K_g decay, where K_g is a hybrid resonance with sbar g q constituents. We show that a K_g resonance of ~ 2 GeV mass and suitably broad width could be behind the excess.Comment: 4 pages, 2 figures. To appear in Phys. Rev.

    Chiral Perturbation Theory for τρπντ\tau \to \rho \pi\nu_\tau, τKπντ\tau \to K^* \pi \nu_\tau, and τωπντ\tau \to \omega \pi \nu_\tau

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    We use heavy vector meson SU(2)L×SU(2)RSU(2)_L \times SU(2)_R chiral perturbation theory to predict differential decay distributions for τρπντ\tau \rightarrow \rho \pi \nu_\tau and τKπντ\tau \rightarrow K^* \pi \nu_\tau in the kinematic region where pVpπ/mVp_V \cdot p_\pi/m_V (here V=ρV = \rho or KK^*) is much smaller than the chiral symmetry breaking scale. Using the large number of colors limit we also predict the rate for τωπντ\tau \rightarrow \omega \pi \nu_\tau in this region (now V=ωV = \omega). Comparing our prediction with experimental data, we determine one of the coupling constants in the heavy vector meson chiral Lagrangian.Comment: 14 pages, latex 2e. We include the decay of the tau into the omega, pi minus and the tau neutrino, and extract a value for the coupling constant g2, using experimental dat

    Semileptonic and nonleptonic B decays to three charm quarks: B->J/psi (eta_c) D l nu and J/psi (eta_c) D pi

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    We evaluate the form factors describing the semileptonic decays B0ˉJ/ψ(ηc)D+νˉ\bar{B^0}\to J/\psi (\eta_c) D^+ \ell^- \bar \nu_\ell, within the framework of a QCD relativistic potential model. This decay is complementary to B0ˉJ/ψ(ηc)D+π\bar{B^0}\to J/\psi (\eta_c) D^+ \pi^- in a phase space region where a pion factors out.We estimate the branching ratio for these semileptonic and nonleptonic channels, finding BR(B0ˉJ/ψ(ηc)D+ν)1013\mathcal{BR}(\bar{B^0} \to J/\psi (\eta_c) D^+ \ell \nu_\ell) \simeq 10^{-13}, BR(B0ˉJ/ψD+π)=3.1×108\mathcal{BR}(\bar{B^0} \to J/\psi D^+ \pi^-) = 3.1 \times 10^{-8} and BR(B0ˉηcD+π)=3.5×108\mathcal{BR}(\bar{B^0} \to \eta_c D^+ \pi^-) = 3.5 \times 10^{-8}.Comment: 14 pages, 4 figure

    Inclusive J/psi and psi(2S) Production from B Decay in p p-bar Collisions

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    Using information on B-meson fragmentation functions from CERN LEP 1 and adopting the nonrelativistic QCD factorization formalism proposed by Bodwin, Braaten, and Lepage, we predict the transverse-momentum distribution of J/psi mesons originating from the inclusive decays of b hadrons produced in p p-bar collisions at the Fermilab Tevatron. We determine the relevant colour-octet charmonium matrix elements from fits to CDF data on prompt charmonium hadroproduction and to CLEO data on charmonium production from B-meson decay. Our predictions are found to agree well with recent CDF and D0 data.Comment: 27 pages (Latex), 9 figures (Postscript

    Observation of the Decay \u3ci\u3eD\u3c/i\u3e\u3csub\u3es\u3c/sub\u3e\u3csup\u3e+\u3c/sup\u3e → ωπ\u3csup\u3e+\u3c/sup\u3e

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    Using e+e- annihilation data collected by the CLEO II detector at CESR, we have observed the decay Ds+ → ωπ+. This final state may be produced through the annihilation decay of the i\u3eDs+, or through final state interactions. We find a branching ratio of γ(Ds+ → ωπ+)/γ(Ds+ →ηπ+) = 0.16±0.04±0.03, where the first error is statistical and the second is systematic

    The Decay D0Kˉ0πe+νeD^0\to \bar K^{*0} \pi^- e^+ \nu_e in the Context of Chiral Perturbation Theory

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    We study the decay D0Kˉ0πe+νeD^0\rightarrow \bar K^{*0} \pi^- e^+ \nu_e, using SU(2)LSU(2)RSU(2)_L \otimes SU(2)_R chiral perturbation theory for heavy charmed mesons and vector mesons, in the kinematic regime where pMpπ/mMp_M \cdot p_\pi/m_M (here M=D0M = D^0 or Kˉ0\bar K^{*0}) is much smaller than the chiral symmetry breaking scale, ΛχSB\Lambda_{\chi SB} ( ΛχSB\Lambda_{\chi SB} \sim 1 GeV). We present the leading diagrams and amplitude, and calculate the rate, in the region where, to leading order in our calculations, the Kˉ0\bar K^{*0} is at zero recoil in the D0D^0 rest frame. The rate thus calculated is given in terms of a known form factor and depends on the DDπDD^* \pi coupling constant gDg_D of the heavy (charmed) meson chiral perturbation theory Lagrangian. A measurement of the above decay, in the aforementioned kinematic regime, can result in the extraction of an experimental value for gDg_D, accurate at the level of our approximations, and give us a measure of the validity of approaches based on chiral perturbation theory in studying similar processes.Comment: 17 pages, Latex, 2 embedded postscript figure

    Evading the CKM Hierarchy: Intrinsic Charm in B Decays

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    We show that the presence of intrinsic charm in the hadrons' light-cone wave functions, even at a few percent level, provides new, competitive decay mechanisms for B decays which are nominally CKM-suppressed. For example, the weak decays of the B-meson to two-body exclusive states consisting of strange plus light hadrons, such as B\to\pi K, are expected to be dominated by penguin contributions since the tree-level b\to s u\bar u decay is CKM suppressed. However, higher Fock states in the B wave function containing charm quark pairs can mediate the decay via a CKM-favored b\to s c\bar c tree-level transition. Such intrinsic charm contributions can be phenomenologically significant. Since they mimic the amplitude structure of ``charming'' penguin contributions, charming penguins need not be penguins at all.Comment: 28 pages, 6 figures, published version. References added, minor change

    Precision Measurement of the Ds+Ds+D_s^{*+}- D_s^+ Mass Difference

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    We have measured the vector-pseudoscalar mass splitting M(Ds+)M(Ds+)=144.22±0.47±0.37MeVM(D_s^{*+})-M(D_s^+) = 144.22\pm 0.47\pm 0.37 MeV, significantly more precise than the previous world average. We minimize the systematic errors by also measuring the vector-pseudoscalar mass difference M(D0)M(D0)M(D^{*0})-M(D^0) using the radiative decay D0D0γD^{*0}\rightarrow D^0\gamma, obtaining [M(Ds+)M(Ds+)][M(D0)M(D0)]=2.09±0.47±0.37MeV[M(D_s^{*+})-M(D_s^+)]-[M(D^{*0})-M(D^0)] = 2.09\pm 0.47\pm 0.37 MeV. This is then combined with our previous high-precision measurement of M(D0)M(D0)M(D^{*0})-M(D^0), which used the decay D0D0π0D^{*0}\rightarrow D^0\pi^0. We also measure the mass difference M(Ds+)M(D+)=99.5±0.6±0.3M(D_s^+)-M(D^+)=99.5\pm 0.6\pm 0.3 MeV, using the ϕπ+\phi\pi^+ decay modes of the Ds+D_s^+ and D+D^+ mesons.Comment: 18 pages uuencoded compressed postscript (process with uudecode then gunzip). hardcopies with figures can be obtained by sending mail to: [email protected]
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