5,279 research outputs found

    Second Order Power Corrections in the Heavy Quark Effective Theory I. Formalism and Meson Form Factors

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    In the heavy quark effective theory, hadronic matrix elements of currents between two hadrons containing a heavy quark are expanded in inverse powers of the heavy quark masses, with coefficients that are functions of the kinematic variable vvv\cdot v'. For the ground state pseudoscalar and vector mesons, this expansion is constructed at order 1/mQ21/m_Q^2. A minimal set of universal form factors is defined in terms of matrix elements of higher dimension operators in the effective theory. The zero recoil normalization conditions following from vector current conservation are derived. Several phenomenological applications of the general results are discussed in detail. It is argued that at zero recoil the semileptonic decay rates for BDνB\to D\,\ell\,\nu and BDνB\to D^*\ell\,\nu receive only small second order corrections, which are unlikely to exceed the level of a few percent. This supports the usefulness of the heavy quark expansion for a reliable determination of VcbV_{cb}.Comment: (34 pages, REVTEX, two postscript figures available upon request), SLAC-PUB-589

    Bounds on R-parity violating supersymmetric couplings from leptonic and semi-leptonic meson decays

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    We present a comprehensive update of the bounds on R-Parity violating supersymmetric couplings from lepton-flavour- and lepton-number-violating decay processes. We consider tau and mu decays as well as leptonic and semi-leptonic decays of mesons. We present several new bounds resulting from tau, eta and Kaon decays and correct some results in the literature concerning B-meson decays.Comment: 30 pages; changed title, updated some bounds from the literature from different references, added reference

    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

    A Consistent Calculation of Heavy Meson Decay Constants and Transition Wave Functions in the Complete HQEFT

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    Within the complete heavy quark effective field theory (HQEFT), the QCD sum rule approach is used to evaluate the decay constants including 1/m_Q corrections and the Isgur-Wise function and other additional important wave functions concerned at 1/m_Q for the heavy-light mesons. The 1/m_Q corrections to the scaling law f_M \sim F/\sqrt{m_M} are found to be small in HQEFT, which demonstrates again the validity of 1/m_Q expansion in HQEFT. It is also shown that the residual momentum v.k of heavy quark within hadrons does be around the binding energy \bar{\Lambda} of the heavy hadrons. The calculations presented in this paper provide a consistent check on the HQEFT and shows that the HQEFT is more reliable than the usual HQET for describing a slightly off-mass shell heavy quark within hadron as the usual HQET seems to lead to the breakdown of 1/m_Q expansion in evaluating the meson decay constants. It is emphasized that the introduction of the `dressed heavy quark' mass is useful for the heavy-light mesons (Qq) with m_Q >> \bar{\Lambda} >> m_q, while for heavy-heavy bound states (\psi_1\psi_2) with masses m_1, m_2 >> \bar{\Lambda}, like bottom-charm hadrons or similarly for muonium in QED, one needs to treat both particles as heavy effective particles via 1/m_1 and 1/m_2 expansions and redefine the effective bound states and modified `dressed heavy quark' masses within the HQEFT.Comment: 20 pages, revtex, 22 figures, axodraw.sty, two irrelevant figures are moved awa

    Exclusive semileptonic B_s decays to excited D_s mesons: Search of D_{sJ}(2317) and D_{sJ}(2460)

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    We study the exclusive semileptonic decays B_s->D_{s0}^*\ell\bar\nu and B_s->D_{s1}^*\ell\bar\nu, where p-wave excited D_{s0}^* and D_{s1}^* states are identified with the newly observed D_{sJ}(2317) and D_{sJ}(2460) states. Within the framework of HQET the Isgur-Wise functions up to the subleading order of the heavy quark expansion are calculated by QCD sum rules. The decay rates and branching ratios are computed with the inclusion of the order of 1/m_Q corrections. We point out that the investigation of the B_s semileptonic decays to excited D_s mesons may provide some information about the nature of the new D_{sJ}^* mesons.Comment: 15 pages, 6 eps figures, RevTeX 4, accepted for publication in Phys. Rev.

    Identifying DsJ(2700)D_{sJ}(2700) through its decay modes

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    We study how to assign the recently observed DsJ(2700)D_{sJ}(2700) meson to an appropriate level of the csˉc \bar s spectrum by the analysis of its decay modes in final states comprising a light pseudoscalar meson. We use an effective lagrangian approach with heavy quark and chiral symmetries, obtaining that the measurement of the DKD^* K decay width would allow to distinguish between two possible assignments.Comment: RevTex, 6 pages - references adde

    Investigations on nucleophilic layers made with a novel plasma jet technique

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    In this work a novel plasma jet technique is used for the deposition of nucleophilic films based on (3-aminopropyl)trimethoxysilane at atmospheric pressure. Film deposition was varied with regard to duty cycles and working distance. Spectral ellipsometry and chemical derivatization with 4-(trifluoromethyl)benzaldehyde using ATR- FTIR spectroscopy measurements were used to characterize the films. It was found that the layer thickness and the film composition are mainly influenced by the duty cycle

    Violations of Local Duality in the Heavy Quark Sector

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    We examine the origin of possible failures of the quark-hadron local duality. In particular, we consider a correlator of two currents comprising heavy quark operators, and compare the evaluation by the Operator Product Expansion with the result obtained inserting an infinite set of hadronic states, in the N_c to infinity limit. Whereas the smeared spectral functions agree with each other, their local behaviour is different. The difference manifests itself in the form of a term O(Lambda/epsilon) (epsilon being the residual energy) that is not present in the expansion in powers of Lambda/epsilon predicted by the OPE.Comment: Latex, 14 pages, 1 figur

    Radiatively corrected shape function for inclusive heavy hadron decays

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    We discuss the non-perturbative and the radiative corrections to inclusive B decays from the point of view known from QED corrections to high energy e^+ e^- processes. Here the leading contributions can be implemented through the so called ``radiator function'' which corresponds to the shape function known in heavy hadron decays. In this way some new insight into the origin of the shape function is obtained. As a byproduct, a parameterization of the radiatively corrected shape function is suggested which can be implemented in Monte Carlo studies of inclusive heavy hadron decays.Comment: LaTeX, uses a4, graphicx and psfrag, 10 pages. The complete paper is also available at http://www-ttp.physik.uni-karlsruhe.de/Preprints

    Two-loop corrections to the Isgur-Wise function in QCD sum rules

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    We complete the QCD sum rule analysis of the Isgur Wise form factor ξ(vv)\xi(v\cdot v') at next-to-leading order in renormalization-group improved perturbation theory. To this end, the exact result for the two-loop corrections to the perturbative contribution is derived using the heavy quark effective theory. Several techniques for the evaluation of two-loop integrals involving two different types of heavy quark propagators are discussed in detail, among them the methods of integration by parts and differential equations. The order-αs\alpha_s corrections to the Isgur-Wise function turn out to be small and well under control. At large recoil, they tend to decrease the form factor by 510%5-10\%.Comment: 24 pages (REVTEX), 2 figures available upon request, SLAC-PUB-599
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