331 research outputs found

    Generalized Coordinate Gauge, Nonabelian Stokes Theorem and Dual QCD Lagrangian

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    This paper is an extended version of hep-th/9802134. Dual QCD Lagrangian is derived by making use of the generalized coordinate gauge, where 1-form (vector potential) is expressed as an integral of the 2-form (field strength) along an (arbitrary) contour. As another application a simple proof of the nonabelian Stokes theorem is given.Comment: LaTeX 13 pages, no figure

    Unitarization of Total Cross Section and Coherent Effect in pQCD

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    A formula to unitarize the leading-log BFKL-Pomeron amplitude is derived using a coherent property of two-body collision in the peripheral region. This procedure also allows an algebraic characterization of the Reggeon in QCD based on color, instead of the total angular momentum of the gluons being exchanged.Comment: Talk given at the DIS99 Meeting in Zeuthen, Germany. April, 1999. 3 page

    Elements of a field theory of unitarity corrections

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    I explain the motivation for investigating the high energy limit of QCD and give a brief presentation of recent progress in the understanding of unitarity corrections in this kinematic regime. Special emphasis is given to the conformal field theory structure discovered in these unitarity corrections.Comment: 4 pages, Talk presented at 7th International Workshop on Deep Inelastic Scattering, Zeuthen, Germany, April 199

    Estimates of higher-dimensional vacuum condensates from the instanton vacuum

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    We calculate the values of non-factorizable dimension-7 vacuum condensates in the instanton vacuum. We comment on a method, recently proposed by Oganesian, to estimate the dimension-7 condensates by factorization of dimension-10 condensates in various inequivalent ways. The instanton estimates could be used to analyze the stability of QCD sum rules with increasing dimensions.Comment: 8 pages, Late

    Influence of working environments on fatigue crack propagation in high nitrogen steels

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    The characteristic parameters dependence under cyclic deformation in hydrogen, chloride environments and the subsequent selective dissolution has been studied. For high nitrogen steels and welded joints it has been established that mechanical stresses accelerate general dissolution of an alloy in different ways and lead to the formation of a surface layer morphology which is different from the original one. Welded joints characterized by a higher corrosion fatigue resistance in all investigated solutions, except saturated cupper chloride solution

    Strong Bootstrap Conditions

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    We reformulate the so-called ``strong bootstrap'' conditions for the gluon Reggeization in the next-to-leading approximation (NLA), firstly suggested by Braun and Vacca, using a different approach, which is not based on properties of the eigenstates of the NLA octet BFKL kernel. We write the second strong bootstrap condition for the NLA octet impact factors in a form which makes clear their dependence on the process. According to this condition, the NLA octet impact factors must be given by the product of the corresponding Reggeon interaction vertices with a universal coefficient function. This function can be used also in the formulation of the first strong bootstrap condition for the NLA BFKL kernel in the octet state.Comment: 10 page

    Baryon stopping and saturation physics in relativistic collisions

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    We investigate baryon transport in relativistic heavy-ion collisions at energies reached at the CERN Super Proton Synchrotron, BNL Relativistic Heavy-Ion Collider (RHIC), and CERN LHC in the model of saturation. An analytical scaling law is derived within the color glass condensate framework based on small-coupling QCD. Transverse momentum spectra, net-baryon rapidity distributions and their energy, mass and centrality dependences are well described. In a comparison with RHIC data in Au + Au collisions at sqrt (s_NN) = 62.4 GeV and 200 GeV, the gradual approach to the gluon saturation regime is investigated, and limits for the saturation-scale exponent are determined. Predictions for net-baryon rapidity spectra and the mean rapidity loss in central Pb + Pb collisions at LHC energies of sqrt (s_NN) = 5.52 TeV are made.Comment: 11 pages, 10 Figures; improved figure inscriptions, corrected typos, minor changes in text/titl

    Baryon Stopping as a new Probe of Geometric Scaling

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    We suggest to use net-baryon rapidity distributions in central relativistic heavy-ion collisions at SPS, RHIC and LHC energies in order to probe saturation physics. Within the color glass condensate framework based on small-coupling QCD, net-baryon rapidity distributions are shown to exhibit geometric scaling. In a comparison with RHIC data in Au + Au collisions at sqrt(s_NN) = 62.4 GeV and 200 GeV the gradual approach to the gluon saturation regime is investigated. Predictions for net-baryon rapidity spectra and the mean rapidity loss in central Pb + Pb collisions at LHC energies of sqrt (s_NN) = 5.5 TeV are made.Comment: 4 pages 3 figures; calculation and figures now for net baryons instead of net protons; modified conclusion

    Running Coupling BFKL Equation and Deep Inelastic Scattering

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    I examine the form of the solution of the BFKL equation with running coupling relevant for deep inelastic scattering. The evolution of structure functions is precisely determined and well described by an effective coupling of the form 1/(beta_0(ln(Q^2/Lambda^2)+3.6(alpha_s(Q^2)ln(1/x))^1/2)) (until very small x). Corrections to the LO equation are relatively small, and the perturbative expansion is stable. Comparison to data via a global fit is very successful.Comment: Latex file uses epsfig.sty and npb.sty, 4 pages including 1 embedded figure. Contribution to the proceedings of the International Workshop on Deep Inelastic Scattering and QCD (DIS99), Zeuthen, April 199

    Modular Invariance and the Odderon

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    We identify a new symmetry for the equations governing odderon amplitudes, corresponding in the Regge limit of QCD to the exchange of 3 reggeized gluons. The symmetry is a modular invariance with respect to the unique normal subgroup of sl(2,Z) {\,} of index 2. This leads to a natural description of the Hamiltonian and conservation-law operators as acting on the moduli space of elliptic curves with a fixed ``sign'': elliptic curves are identified if they can be transformed into each other by an {\em even} number of Dehn twists.Comment: 9 pages, LaTeX, uses amssym.def for \Bbb 'blackboard math' font
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