427 research outputs found

    Interactions of Heavy Hadrons using Regge Phenomenology and the Quark Gluon String Model

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    The search for stable heavy exotic hadrons is a promising way to observe new physics processes at collider experiments. The discovery potential for such particles can be enhanced or suppressed by their interactions with detector material. This paper describes a model for the interactions in matter of stable hadrons containing an exotic quark of charges ±1/3e\pm {1/3}e or ±2/3e\pm {2/3}e using Regge phenomenology and the Quark Gluon String Model. The influence of such interactions on searches at the LHC is also discussed

    Vibrating the QCD string

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    The large distance behaviour of the adiabatic hybrid potentials is studied in the framework of the QCD string model. The calculated spectra are shown to be the result of interplay between potential-type longitudinal and string-type transverse vibrations.Comment: LaTeX2e, 9 pages, 2 Postscript figures, final version to appear in Yad.Fi

    DTUJET--93 Sampling inelastic proton--proton and antiproton--proton collisions according to the two--component Dual Parton Model

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    A new version of a Monte Carlo Program for hadronic multi-particle production is presented. It is based on the two-component Dual Parton Model which includes the dual topological unitarization of soft and hard cross sections. The model treats both soft (low pp_{\perp}) and hard (minijet, large pp_{\perp}) processes in a unified and consistent way. The unified description is important at TeV-energies of hadron colliders, where the hard perturbative cross sections of QCD become large and comparable to the total cross sections.Comment: 20 pages , PHYSZZX, SI-93-

    Quark-Gluon String Model Description of Baryon Production in K^{\pm}N Interactions

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    The process of baryon production in K p collisions at high energies is considered in the framework of the Quark-Gluon String Model. The contribution of the string-junction mechanism to the strange baryon production is analysed. The results of numerical calculations are in reasonable agreement with the data on inclusive spectra of p, Lambda, bar{Lambda}, and on the bar{Lambda}/Lambda asymmetry. The predictions for Xi and Omega baryons are presented.Comment: 19 pages, 7 figure

    Triangular and Y-shaped hadrons in QCD

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    Gauge invariant extended configurations are considered for the three fundamental (quarks) or adjoint (gluons) particles. For quarks it is shown that the Y-shaped configuration is the only possible. For adjoint sources both the Y-shaped and triangular configurations may realize. The corresponding static potentials are calculated in the Method of Field Correlators and in the case of baryon shown to be consistent with the lattice simulations. For adjoint sources the potentials of Y-shaped and Delta-shaped configurations turn out to be close to each other, which leads to almost degenerate masses of 3-- 3g glueballs and odderon trajectories.Comment: 9 pages, 5 eps figures, latex2e, one reference adde

    Baryon stopping and hyperon enhancement in the improved dual parton model

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    We present an improved version of the dual parton model which contains a new realization of the diquark breaking mechanism of baryon stopping. We reproduce in this way the net baryon yield in nuclear collisions. The model, which also considers strings originating from diquark-antidiquark pairs in the nucleon sea, reproduces the observed yields of p and Lambda and their antiparticles and underestimates cascades by less than 50 %. However, Omega's are underestimated by a factor five. Agreement with data is restored by final state interaction, with an averaged cross-section as small as 0.14 mb. Hyperon yields increase significantly faster than antihyperons, in agreement with experiment.Comment: 40 pages, 18 postscript figure

    Feynman scaling violation on baryon spectra in pp collisions at LHC and cosmic ray energies

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    A significant asymmetry in baryon/antibaryon yields in the central region of high energy collisions is observed when the initial state has non-zero baryon charge. This asymmetry is connected with the possibility of baryon charge diffusion in rapidity space. Such a diffusion should decrease the baryon charge in the fragmentation region and translate into the corresponding decrease of the multiplicity of leading baryons. As a result, a new mechanism for Feynman scaling violation in the fragmentation region is obtained. Another numerically more significant reason for the Feynman scaling violation comes from the fact that the average number of cutted Pomerons increases with initial energy. We present the quantitative predictions of the Quark-Gluon String Model (QGSM) for the Feynman scaling violation at LHC energies and at even higher energies that can be important for cosmic ray physics.Comment: 21 pages, 11 figures, and 1 table. arXiv admin note: substantial text overlap with arXiv:1107.1615, arXiv:1007.320

    Factorization and Scaling in Hadronic Diffraction

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    In standard Regge theory with a pomeron intercept a(0)=1+\epsilon, the contribution of the tripe-pomeron amplitude to the t=0 differential cross section for single diffraction dissociation has the form d\sigma/dM^2(t=0) \sim s^{2\epsilon}/(M^2)^{1+\epsilon}. For \epsilon>0, this form, which is based on factorization, does not scale with energy. From an analysis of p-p and p-pbar data from fixed target to collider energies, we find that such scaling actually holds, signaling a breakdown of factorization. Phenomenologically, this result can be obtained from a scaling law in diffraction, which is embedded in the hypothesis of pomeron flux renormalization introduced to unitarize the triple pomeron amplitude.Comment: 39 pages, Latex, 16 figure

    On recent puzzles in the production of heavy quarkonia

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    Recently, several surprising experimental observations in the production of heavy quarkonium have been reported. In e+ee^+e^- annihilation at s=10.6\sqrt{s}=10.6 GeV, Belle Collaboration finds that J/ψJ/\psi mesons are predominantly produced in association with an extra cˉc\bar{c}c pair, with σ(e+eJ/ψcˉc)/σ(e+eJ/ψX)=0.590.13+0.15±0.12\sigma(e^+e^- \to J/\psi \bar{c}c) / \sigma(e^+e^- \to J/\psi X) = 0.59^{+0.15}_{-0.13}\pm 0.12, and the BaBar collaboration reports that the produced J/ψJ/\psi's have mostly longitudinal polarization. In pˉp\bar{p}p collisions at the Tevatron, the CDF Collaboration reported an excess of J/ψJ/\psi and ψ\psi^{\prime} mesons at high pp_{\perp} over the perturbative QCD predictions; non--perturbative approach of NRQCD can accomodate the magnitude of the production cross section but not the observed experimentally polarization of quarkonia. In this note we propose possible solutions to these puzzles, and devise further experimental tests.Comment: 3 pages, 2 figure

    On the role of the final state interactions in rare B-decays

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    The effects of final state interactions (FSI) in hadronic B-decays are investigated. The model for FSI, based on Regge phenomenology of high-energy hadronic interactions is proposed. It is shown that this model explains the pattern of phases in matrix elements of BππB\to\pi\pi and BρρB\to\rho\rho decays. These phases play an important role for CP-violation in B-decays. The most precise determination of the unitarity triangle angle α\alpha from BdρπB_d\to \rho\pi decays is performed. The relation between CP-asymmetries in BKπB\to K\pi decays is discussed. It is emphasized that the large distance FSI can explain the structure of polarizations of the vector mesons in B-decays and other puzzles like a very large branching ratio of the B-decay to ΞˉcΛc\bar\Xi_c\Lambda_c.Comment: 19 page
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