74 research outputs found

    Charmless Three-body Decays of B Mesons

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    Charmless 3-body decays of B mesons are studied in the framework of the factorization approach. The nonresonant contributions arising from BP1P2B\to P_1P_2 transitions are evaluated using heavy meson chiral perturbation theory (HMChPT). The momentum dependence of nonresonant amplitudes is assumed to be in the exponential form e^{-\alpha_{NR}} p_B\cdot(p_i+p_j)} so that the HMChPT results are recovered in the soft meson limit pi,pj0p_i, p_j\to 0. In addition, we have identified another large source of the nonresonant signal in the matrix elements of scalar densities, e.g. , which can be constrained from the decay Bˉ0KSKSKS\bar B^0\to K_SK_SK_S or BKKSKSB^-\to K^-K_SK_S. The intermediate vector meson contributions to 3-body decays are identified through the vector current, while the scalar meson resonances are mainly associated with the scalar density. Their effects are described in terms of the Breit-Wigner formalism. Our main results are: (i) All KKK modes are dominated by the nonresonant background. The predicted branching ratios of K+KKS(L)K^+K^-K_{S(L)}, K+KKK^+K^-K^- and KKSKSK^-K_SK_S modes are consistent with the data within errors. (ii) Although the penguin-dominated B0K+KKSB^0\to K^+K^-K_{S} decay is subject to a potentially significant tree pollution, its effective sin2β\sin 2\beta is very similar to that of the KSKSKSK_SK_SK_S mode. However, direct CP asymmetry of the former, being of order -4%, is more prominent than the latter. (iii) For BKππB\to K\pi\pi decays, we found sizable nonresonant contributions in Kπ+πK^-\pi^+\pi^- and Kˉ0π+π\bar K^0\pi^+\pi^- modes, in agreement with the Belle measurements but larger than the BaBar result.Comment: 39 pages, 2 figures, version to appear in PR

    Simulation of neutrino and charged particle production and propagation in the atmosphere

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    A precise evaluation of the secondary particle production and propagation in the atmosphere is very important for the atmospheric neutrino oscillation studies. The issue is addressed with the extension of a previously developed full 3-Dimensional Monte-Carlo simulation of particle generation and transport in the atmosphere, to compute the flux of secondary protons, muons and neutrinos. Recent balloon borne experiments have performed a set of accurate flux measurements for different particle species at different altitudes in the atmosphere, which can be used to test the calculations for the atmospheric neutrino production, and constrain the underlying hadronic models. The simulation results are reported and compared with the latest flux measurements. It is shown that the level of precision reached by these experiments could be used to constrain the nuclear models used in the simulation. The implication of these results for the atmospheric neutrino flux calculation are discussed.Comment: 11 pages, 9 figure

    Heavy--light mesons in a bilocal effective theory

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    Heavy--light mesons are described in an effective quark theory with a two--body vector--type interaction. The bilocal interaction is taken to be instantaneous in the rest frame of the bound state, but formulated covariantly through the use of a boost vector. The chiral symmetry of the light flavor is broken spontaneously at mean field level. The framework for our discussion of bound states is the effective bilocal meson action obtained by bosonization of the quark theory. Mesons are described by 3--dimensional wave functions satisfying Salpeter equations, which exhibit both Goldstone solutions in the chiral limit and heavy--quark symmetry for mQm_Q\rightarrow\infty. We present numerical solutions for pseudoscalar DD-- and BB--mesons. Heavy--light meson spectra and decay constants are seen to be sensitive to the description of chiral symmetry breaking (dynamically generated vs.\ constant quark mass).Comment: (34 p., standard LaTeX, 7 PostScript figures appended) UNITUE-THEP-17/9

    f [N pi N]: from quarks to the pion derivative coupling

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    We study the N pi N coupling, in the framework of a QCD-inspired confining Nambu-Jona-Lasinio model. A simple relativistic confining and instantaneous quark model is reviewed. The Salpeter equation for the nucleon and the boosted pion is solved. The f [n pi n] and f[n pi Delta] couplings are calculated and they turn out to be reasonably good. The sensibility of f[n pi n] and f[n pi Delta] to confinement, chiral symmetry breaking and Lorentz invariance is briefly discussed.Comment: 30 pages in LaTex RevTex, 6 postscript figure

    Monopole Vacuum in Non-Abelian Theories

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    It is shown that, in the theory of interacting Yang -Mills fields and a Higgs field, there is a topological degeneracy of Bogomol'nyi-Prasad-Sommerfield (BPS) monopoles and that there arises, in this case, a chromoelectric monopole characterized by a new topological variable that describes transitions between topological states of the monopole in the Minkowski space (in just the same way as an instanton describes such transitions in the Euclidean space). The limit of an infinitely large mass of the Higgs field at a finite density of the BPS monopole is considered as a model of the stable vacuum in the pure Yang-Mills theory. It is shown that, in QCD, such a monopole vacuum may lead to a rising potential, a topological confinement and an additional mass of the η0\eta_0 meson. The relationship between the result obtained here for the generating functional of perturbation theory and Faddeev-Popov integral is discussed

    Repulsive Core of NN S-Wave Scattering in a Quark Model with a Condensed Vacuum

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    We work in a chiral invariant quark model, with a condensed vacuum, characterized by only one parameter. Bound state equations for the nucleon and Delta are solved in order to obtain an updated value of their radii and masses. Nucleon-nucleon S-Wave scattering is studied in the RGM framework both for isospin T=1 and T=0. The phase shifts are calculated and an equivalent local potential, which is consistent with K-N scattering, is derived. The result is a reasonable microscopic short range repulsion in the nucleon-nucleon interaction.Comment: 23 pages in latex revtex, 4 Postscript figure

    Heavy- to light-meson transition form factors

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    Semileptonic heavy -> heavy and heavy -> light meson transitions are studied as a phenomenological application of a heavy-quark limit of Dyson-Schwinger equations. Employing two parameters: E, the difference between the mass of the heavy meson and the effective-mass of the heavy quark; and Lambda, the width of the heavy-meson Bethe-Salpeter amplitude, we calculate f_+(t) for all decays on their entire kinematically accessible t-domain. Our study favours f_B in the range 0.135-0.17 GeV and with E=0.44 GeV and 1/Lambda = 0.14 fm we obtain f_+^{B pi}(0) = 0.46. As a result of neglecting 1/m_c-corrections, we estimate that our calculated values of \rho^2 = 0.87 and f_+^{DK}(0)=0.62 are too low by approximately 15%. However, the bulk of these corrections should cancel in our calculated values of Br(D -> \pi l nu)/Br(D -> K l nu)=0.13 and f_+^{D pi}(0)/f_+^{DK}(0) = 1.16.Comment: 26 pages, 3 figures, REVTE

    Atmospheric muon flux at PeV energies

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    In the near future the energy region above few hundreds of TeV may really be accessible for measurements of the atmospheric muon spectrum by the IceCube array. Therefore one expects that muon flux uncertainties above 50 TeV, related to a poor knowledge of charm production cross sections and insufficiently examined primary spectra and composition, will be diminished. We give predictions for the very high-energy muon spectrum at sea level, obtained with the three hadronic interaction models, taking into account also the muon contribution due to decays of the charmed hadrons.Comment: 8 pages, 3 figures. The version published in Int. J. Mod. Phys.

    Chiral symmetry breaking solutions for QCD in the truncated Coulomb gauge

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    In this paper we study the power-like confining potentials r^alpha. The region of allowed alphas is identified, the mass-gap equation is constructed for an arbitrary alpha and solved for several values of the latter, and the vacuum energy and the chiral condensate are calculated. The question of replica solutions to the mass-gap equation for such potentials is addressed and it is demonstrated that the number of replicas is infinite for any alpha, as a consequence of the peculiar behaviour of the quark self-energy in the infrared domain.Comment: RevTeX4, 18 pages, 3 Postscript figures, uses epsfig.sty, to appear in Phys.Rev.

    EXAMINATION AND TESTING OF EXPERIMENTAL-PRODUCTION SERIES OF POLYVALENT BRUCELLOSIS SERUM

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    At present no commercial polyvalent brucellosis serum is produced in Russia. We developed a technology of polyvalent brucellosis high-effective and specific serum production without adsorption. Experimental-production series are obeyed the technical specification project
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