594 research outputs found

    Branching ratios of the decays of psi(3770) and Upsilon(10580) into light hadrons

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    Taking into account the new data on the full width of D^{\ast\pm}(2010) and the mass difference of the charged and neutral beauty mesons B^\pm, B^0,\bar B^0, the branching ratios of the decays psi(3770), Upsilon(10580) to pi^+pi^-, K bar K, rho(omega)pi, rho(omega)eta, rho(omega)eta^prime, K^ast bar K+ c.c, rho^+ rho^-, and K^ast bar K^ast are re-evaluated in the model in which the Okubo-Zweig-Iizuka rule is violated due to the real intermediate state D\bar D in case of psi(3770) and B\bar B in case of Upsilon(10580). The inclusive annihilation of psi(3770) and Upsilon(10580) into light hadrons is discussed.Comment: 10 page

    The effective action and equations of motion of curved local and global vortices: Role of the field excitations

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    The effective actions for both local and global curved vortices are derived, based on the derivative expansion of the corresponding field theoretic actions of the nonrelativistic Abelian Higgs and Goldstone models. The role of excitations of the modulus and the phase of the scalar field and of the gauge field (the Bogolyubov-Anderson mode) emitted and reabsorbed by vortices is elucidated. In case of the local (gauge) magnetic vortex, they are necessary for cancellation of the long distance divergence when using the transverse form of the electric gauge field strength of the background field. In case of global vortex taking them into account results in the Greiter-Wilczek-Witten form of the effective action for the Goldstone mode. The expressions for transverse Magnus-like force and the vortex effective mass for both local and global vortices are found. The equations of motion of both type of vortices including the terms due to the field excitations are obtained and solved in cases of large and small contour displacements.Comment: 16 pages, no figures; accepted for publication in Int. Journ. Mod. Phys.

    Isoscalar resonances with J^{PC}=1^{--} in e^+e^-annihilation

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    The analysis of the vector isoscalar excitations in the energy range between 1 and 2 GeV of the e+ee^+e^- annihilation is presented for the final states π+ππ0\pi^+\pi^-\pi^0, ωπ+π\omega\pi^+\pi^-, K+KK^+K^-, KS0K±πK^0_SK^\pm\pi^\mp and K0Kπ++c.cK^{\ast0}K^-\pi^++ c.c. The effects of both the resonance mixing and the successive opening of multiparticle channels, with the energy dependent partial widths, are taken into account. The work extends our previous analysis hep-ph/9609216 of the vector isovector excitations and is aimed to compare the existing data with the predictions of the qqˉq\bar q model. It is shown that this hypothesis does not contradict the data.Comment: 16 pages, revtex, 6 ps figures. Clarifying remarks, a table, and references are added. Accepted in Phys. Rev.

    REDUCING THE MAGNETIC VISCOSITY EFFECT ON TEM SOUNDING DATA

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    Siberian Traps magnetic viscosity affects and makes it difficult to interpret TEM sounding data obtained during oil and gas exploration in the south of the Siberian platform. In this paper, we present and discuss a method for decreasing magnetic viscosity effect on TEM data. The method is based on estimating magnetic viscosity contribution to the total transient response using TEM data measured with multi-offset arrays

    Gauge vortex dynamics at finite mass of bosonic fields

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    The simple derivation of the string equation of motion adopted in the nonrelativistic case is presented, paying the special attention to the effects of finite masses of bosonic fields of an Abelian Higgs model. The role of the finite mass effects in the evaluation of various topological characteristics of the closed strings is discussed. The rate of the dissipationless helicity change is calculated. It is demonstrated how the conservation of the sum of the twisting and writhing numbers of the string is recovered despite the changing helicity.Comment: considerably revised to include errata to journal versio

    Red Light-Emitting Electrochemical Cells Employing Pyridazine-Bridged Cationic Diiridium Complexes

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    A rigid dinuclear Ir(III) complex showing high photoluminescence quantum yield in pure films was successfully used to fabricate light-emitting electrochemical cells with and without ionic liquid additives. The devices showed nearly instantaneous electroluminescence after biasing and maximum quantum yield approaching 1%. The lifetime of the devices was found to be limited to approximately 20 hours, which we correlated with the irreversible oxidation of the complex as seen from electrochemical measurements. This work validates the use of highly luminescent dinuclear iridium complexes in light-emitting electrochemical cells. Future studies will pursue materials with more efficient photoluminescence as well as improved electrochemical stability

    Non-equilibrium current noise in mesoscopic disordered SNS junctions

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    Current noise in superconductor-normal metal-superconductor (SNS) junctions is calculated within the scattering theory of multiple Andreev reflections (MAR). It is shown that the noise exhibits subharmonic gap singularities at eV=2Δ/neV=2\Delta/n, n=1,2,...n=1,2,... both in single-mode junctions with arbitrary transparency DD and in multi-mode disordered junctions. The subharmonic structure is superimposed with monotonic increase of the effective transferred charge q=SI(0)/2Iq^*=S_I(0)/2I with decreasing bias voltage. Other features of the noise include a step-like increase of qq^* in junctions with small DD, and a divergence SI(0)V1/2S_I(0) \propto V^{-1/2} at small voltages and excess noise Sex=2eIexS_{ex} = 2eI_{ex}, where IexI_{ex} is the excess current, at large voltages, in junctions with diffusive transport.Comment: 5 page

    Semiclassical theory of shot noise in disordered SN contacts

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    We present a semiclassical theory of shot noise in diffusive superconductor - normal metal contacts. At subgap voltages, we reproduce the doubling of shot noise with respect to conventional normal-metal contacts, which is interpreted in terms of an energy balance of electrons. Above the gap, the voltage dependence of the noise crosses over to the standard one with a voltage-independent excess noise. The semiclassical description of noise leads to correlations between currents at different electrodes of multiterminal SN contacts which are always of fermionic type, i.e. negative. Using a quantum extension of the Boltzmann - Langevin method, we reproduce the peculiarity of noise at the Josephson frequency and obtain an analytical frequency dependence of noise at above-gap voltages.Comment: 4 pages RevTeX, 1 eps figur

    Coulomb Parameter U and Correlation Strength in LaFeAsO

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    First principles constrained density functional theory scheme in Wannier functions formalism has been used to calculate Coulomb repulsion U and Hund's exchange J parameters for iron 3d electrons in LaFeAsO. Results strongly depend on the basis set used in calculations: when O-2p, As-4p, and Fe-3d orbitals and corresponding bands are included, computation results in U=3-4 eV, however, with the basis set restricted to Fe-3d orbitals and bands only, computation gives parameters corresponding to F^0=0.8 eV, J=0.5 eV. LDA+DMFT (the Local Density Approximation combined with the Dynamical Mean-Field Theory) calculation with this parameters results in weakly correlated electronic structure that is in agreement with X-ray experimental spectra
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