22,055 research outputs found

    Rescattering effects in hadron-nucleus and heavy-ion collisions

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    We review the extension of the factorization formalism of perturbative QCD to {\it coherent} soft rescattering associated with hard scattering in high energy nuclear collisions. We emphasize the ability to quantify high order corrections and the predictive power of factorization approach in terms of universal nonperturbative matrix elements. Although coherent rescattering effects are power suppressed by hard scales of the scattering, they are enhanced by the nuclear size and could play an important role in understanding the novel nuclear dependence observed in high energy nuclear collisions.Comment: 8 pages, 13 figures, to be published in the Proceedings of 1st International Conference on Hard and Electromagnetic Probes of High Energy Nuclear Collisions (Hard Probe 2004), Ericeira, Portugal, Nov. 4-10, 200

    Nuclear enhanced power corrections to DIS structure functions

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    We calculate nuclear enhanced power corrections to structure functions measured in deeply inelastic lepton-nucleus scattering in Quantum Chromodynamics (QCD). We find that the nuclear medium enhanced power corrections at order of O(αs/Q2)O(\alpha_s/Q^2) enhance the longitudinal structure function FLF_L, and suppress the transverse structure function F1F_1. We demonstrate that strong nuclear effects in σA/σD\sigma_A/\sigma_D and RA/RDR_A/R_D, recently observed by HERMES Collaboration, can be explained in terms of the nuclear enhanced power corrections.Comment: Latex, 10 pages including 3 figure

    Breakdown of Conventional Factorization for Isolated Photon Cross Sections

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    Using e+e−→γ+Xe^+e^-\rightarrow\gamma + X as an example, we show that the conventional factorization theorem in perturbative quantum chromodynamics breaks down for isolated photon cross sections in a well defined part of phase space. Implications and physical consequences are discussed.Comment: 11 pages, RevTex, 1 figure in postscrip

    Generalizations of Bernoulli's Numbers and Polynomials

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