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  • 1
    Electronic Resource
    Electronic Resource
    ENERGY LOSS IN PERTURBATIVE QCD (2000)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Nuclear and Particle Science 50 (2000), S. 37-69 
    Details
    ISSN: 0163-8998
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Physics
    Notes: Abstract We review the propagation of energetic partons in hot or cold QCD matter, as known from recent work. We summarize advances in the understanding of both collisional and radiative energy loss. Our emphasis is on radiative energy loss, which has very interesting properties that may help to detect the quark-gluon plasma produced in heavy-ion collisions. We describe two different theoretical approaches, which lead to the same radiated gluon energy spectrum. The case of a longitudinally expanding QCD plasma is investigated. The energy lost by a jet with given opening angle is calculated with the aim of making predictions for the suppression (quenching) of hard jet production. Phenomenological implications for the difference between hot and cold matter are discussed. Numerical estimates of the loss suggest that it may be significantly greater in hot matter than in cold. This makes the magnitude of the radiative energy loss a remarkable signal for quark-gluon plasma formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.nucl.50.1.37
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  • 2
    Electronic Resource
    Electronic Resource
    Colour transparency and scaling properties of nuclear shadowing in deep inelastic scattering (1991)
    Springer
    The European physical journal 49 (1991), S. 607-618 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present the perturbative QCD analysis of nuclear shadowing in the deep inelastic scattering at smallx in terms of the spatial wave function ofq $$\bar q$$ fluctuations of virtual photons. The wave function formalism makes it quite obvious that shadowing is the scaling, rather than the higher twist, 1/Q 2, effect, contrary to a numerous recent claims. We demonstrate explicitly how the scaling shadowing comes from the large, hadronic, size quarkantiquark pairs even in the limit ofQ 2→∞, and why it should very slowly, ∞1/log (Q 2/m 2) decrease at very largeQ 2. We argue in favor of the scaling triple-pomeron contribution to the nuclear shadowing and present predictions for a cross section of diffraction dissociation of virtual photons and for the mass spectrum of diffraction excitation, which can be checked at HERA and Fermilab. We predict strikingly different scaling properties of diffraction dissociation and nuclear shadowing for the longitudinal and transverse photons. Our, numerial predictions for shadowing are in good agreement with the recent EMC data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01483577
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  • 3
    Electronic Resource
    Electronic Resource
    Structure functions of bound nucleons: From the EMC effect to nuclear shadowing (1993)
    Springer
    The European physical journal 58 (1993), S. 541-558 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We describe the nuclear structure functions in the whole range of the Bjorken variablex, by combining various effects in a many-step procedure. First, we present a QCD motivated model of nucleons, treated, in the limit of vanishingQ 2, as bound states of three relativistic constituent quarks. Gluons and sea quarks are generated radiatively from the input valence quarks. All parton distributions are described in terms of the confinement (or nucleon's) radius. The results for free nucleons are in agreement with the experimental determinations. The structure functions of bound nucleons are calculated by assuming that the main effect of nucleon binding is stretching of nucleons. The larger size of bound nucleons lowers the valence momentum and enhances the radiatively generated glue and sea densities. In the small-x region the competitive mechanism of nuclear shadowing takes place. It also depends on the size of the nucleons. By combining stretching, shadowing and Fermi motion effects (the latter confined to very largex), the structure function ratio is well reproduced. Results are also presented for theA-dependence of the momentum integral of charged partons, the nuclear gluon distribution and the hadron-nuclei cross sections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01553013
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  • 4
    Electronic Resource
    Electronic Resource
    Unusual effects of diffraction dissociation for multiproduction in deep inelastic scattering on nuclei (1995)
    Springer
    The European physical journal 351 (1995), S. 435-446 
    Details
    ISSN: 1434-601X
    Keywords: 24.85.+p ; 11.80.La ; 13.60.Hb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In hadron-nucleus interactions, the stronger is nuclear shadowing in the total cross section the higher is the multiplicity of secondary hadrons. In deep inelastic scattering nuclear shadowing at smallx is associated with the hadronlike behaviour of photons as contrasted to the pointlike behaviour in the non-shadowing region of largex. In this paper we predict dilution of multiproduction of secondary hadrons, and weaker fragmentation of the target nucleus, in deep inelastic leptoptoproduction on nuclei in the shadowing region of smallx as compared to the non-shadowing region of largex. This paradoxial conclusion has its origin in nuclear enhancement of the coherent diffraction dissociation of photons which affects multiproduction in the shadowing region and does not contribute in the non-shadowing region. We present numerical predictions for multiproduction in theμXe interactions studied by the Fermilab E665 collaboration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01291149
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  • 5
    Electronic Resource
    Electronic Resource
    Fully quantum treatment of the Landau-Pomeranchik-Migdal effect in QED and QCD (1996)
    Springer
    JETP letters 63 (1996), S. 952-957 
    Details
    ISSN: 1090-6487
    Keywords: 12.20.Ds ; 12.38.−t ; 11.80.Lq
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A rigorous quantum treatment of the Landau-Pomeranchuk-Migdal effect in QED and QCD is given for the first time. The rate of photon (gluon) radiation by an electron (quark) in a medium is expressed in terms of the Green’s function of a two-dimensional Schrödinger equation with an imaginary potential. In QED this potential is proportional to the dipole cross section for scattering of an e + e − pair off an atom, while in QCD it is proportional to the cross section of interaction of the color singlet quark-antiquark-gluon system with a color center.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567126
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  • 6
    Electronic Resource
    Electronic Resource
    The BFKL-Regge phenomenology of deep inelastic scattering (1997)
    Springer
    JETP letters 66 (1997), S. 138-143 
    Details
    ISSN: 1090-6487
    Keywords: 11.55.Jy ; 12.40.Nn
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We calculate the Regge trajectories of the subleading BFKL singularities and eigenfunctions for the running BFKL pomeron in the color dipole representation. We obtain a viable BFKL-Regge expansion of the proton structure function F 2p (x,Q 2) in terms of several rightmost BFKL singularities. We find large subleading contributions to F 2p (x,Q 2) in the HERA kinematical region which explain the lack of predictive power of GLDAP extrapolations of F 2p (x,Q 2) to the region of small x. We point out the relation of our early finding of precocious BFKL asymptotic behavior to the nodal structure of subleading BFKL eigenfunctions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567491
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  • 7
    Electronic Resource
    Electronic Resource
    Diffractive vector mesons beyond the s-channel helicity conservation (1998)
    Springer
    JETP letters 68 (1998), S. 696-703 
    Details
    ISSN: 1090-6487
    Keywords: 13.60.Le ; 12.20.Ds ; 14.40.−n
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We derive a full set, and determine the twist, of helicity amplitudes for diffractive production of light to heavy vector mesons in deep inelastic scattering. For large Q 2 all helicity amplitudes but the double-flip are calculable in perturbative QCD and are proportional to the gluon structure function of the proton at a similar hardness scale. We find a substantial breaking of the s-channel helicity conservation, which must persist in real photoproduction also.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567931
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  • 8
    Electronic Resource
    Electronic Resource
    Predictions for the forward cone in diffractive deep inelastic scattering (1998)
    Springer
    JETP letters 68 (1998), S. 634-640 
    Details
    ISSN: 1090-6487
    Keywords: 13.60.Hb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We calculate the diffraction slope B D for diffractive deep inelastic scattering. We find a counterintuitive rise of B D in going from exclusive diffractive excitation of vector mesons to excitation of continuum states with M 2∼Q 2. For the small-mass continuum we predict a rapid variation of B D with M 2 on a scale of m V 2 and a sharp drop of B D for a small-mass continuum above the vector meson excitation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567920
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  • 9
    Electronic Resource
    Electronic Resource
    Consistent treatment of color transparency effects in diffractive electroproduction of vector mesons off nuclei (1997)
    Springer
    Journal of experimental and theoretical physics 84 (1997), S. 421-431 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Nuclear transparency for incoherent real and virtual photoproduction of vector mesons off nuclei depends crucially on the interplay of the initial-state and final-state interactions. We develop a consistent description of initial-state and final-state interactions based on the coupled-channel multiple-scattering theory. We present detailed predictions for incoherent production of ss̄ and cc̄ mesons. The onset of initial-state interactions is controlled by the production length l P, and we find strong variations of nuclear transparency when l P rises with energy and becomes comparable to the radius of the target nucleus R A. For ss̄ mesons, the regime l P∼R A corresponds to precisely the kinematic range of the HERA-HERMES experiment, whereas for cc̄ mesons the same condition will be met at the ENC electron-nucleus collider at GSI. In spite of the subasymptotic values of Q 2 and v, we find a complex pattern of color transparency-induced effects whose experimental study may provide information on several issues relevant to the understanding of QCD, both in the perturbative and nonperturbative regimes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558158
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  • 10
    Electronic Resource
    Electronic Resource
    The diffraction cone for exclusive vector meson production in deep inelastic scattering (1998)
    Springer
    Journal of experimental and theoretical physics 86 (1998), S. 1054-1073 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We develop the color dipole gBFKL phenomenology of a diffraction cone for photo-and electroproduction γ*N−VN of heavy vector mesons (charmonium & bottomonium) at HERA and in fixed target experiments. We predict a substantial shrinkage of the diffraction cone from the CERN/FNAL to the HERA range of c.m.s. energy W. The Q 2-controlled sensitivity to the color dipole size (scanning phenomenon) is shown to lead to a decrease of the diffraction slope with Q 2 (which is supported by the available experimental data). We predict an approximate flavor independence of the diffraction slope in the scaling variable Q 2+m V 2 . For diffractive production of the radially excited 2S states (Ψ′, γ′), a counterintuitive inequality of diffraction slopes B(2S)≲B(1S) is predicted, which defies the common wisdom that diffraction slopes are larger for reactions with larger size particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558573
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