259 research outputs found

    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

    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.

    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

    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

    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

    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

    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

    b-physics signals of the lightest CP-odd Higgs in the NMSSM at large tan beta

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    We investigate the low energy phenomenology of the lighter pseudoscalar A10A_1^0 in the NMSSM. The A10A_1^0 mass can naturally be small due to a global U(1)RU(1)_R symmetry of the Higgs potential, which is only broken by trilinear soft terms. The A10A_1^0 mass is further protected from renormalization group effects in the large tanβ\tan \beta limit. We calculate the bsA10b \to s A_1^0 amplitude at leading order in tanβ\tan \beta and work out the contributions to rare KK, BB and radiative Υ\Upsilon-decays and BBˉB -\bar B mixing. We obtain constraints on the A10A_1^0 mass and couplings and show that masses down to O(10){\cal{O}}(10) MeV are allowed. The bb-physics phenomenology of the NMSSM differs from the MSSM in the appearance of sizeable renormalization effects from neutral Higgses to the photon and gluon dipole operators and the breakdown of the MSSM correlation between the Bsμ+μB_s \to \mu^+ \mu^- branching ratio and BsBˉsB_s - \bar B_s mixing. For A10A_1^0 masses above the tau threshold the A10A_1^0 can be searched for in bsτ+τb \to s \tau^+ \tau^- processes with branching ratios \lsim 10^{-3}.Comment: 18 pages, 3 figures; references adde

    Probing for the Charm Content of BB and Υ\Upsilon Mesons

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    A slow J/ψJ/\psi bump exists in the inclusive BJ/ψ+XB\to J/\psi + X spectrum, while the softness of J/ψJ/\psi spectrum in Υ(1S)J/ψ+X\Upsilon(1S) \to J/\psi + X decay is in strong contrast with expectations from color octet mechanism. We propose {\it intrinsic} charm as the explanation:the former is due to BˉJ/ψDπ\bar B\to J/\psi D \pi,with three charm quarks in the final state; the latter is just a small fraction of Υ(1S)(ccˉ)slow+2\Upsilon(1S) \to (c\bar c)_{\rm slow} + 2"jet" events, where the slow moving ccˉc\bar c system evolves into D()D^{(*)} pairs. Experimental search for these phenomena at B Factories and the Tevatron is strongly urged, as the implications go beyond QCD.Comment: 4 pages, REVTEX, 10 eps figures included. Major revision with more discussions on the rescattering background, and a reappraisal of the Upsilon(1S) decay in the presence of intrinsic charm, leading to a change in Titl
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