Coherent QCD multiple scattering in proton-nucleus collisions

We argue that high energy proton-nucleus (p+A) collisions provide an excellent laboratory for studying nuclear size enhanced parton multiple scattering where power corrections to the leading twist perturbative QCD factorization approach can be systematically computed. We identify and resum these corrections and calculate the centrality and rapidity dependent nuclear suppression of single and double inclusive hadron production at moderate transverse momenta. We demonstrate that both spectra and dihadron correlations in p+A reactions are sensitive measures of such dynamical nuclear attenuation effectsComment: 5 pages, 3 figures. Updated figures and reference

Rescattering effects in hadron-nucleus and heavy-ion collisions

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

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 $O(\alpha_s/Q^2)$ enhance the longitudinal structure function $F_L$, and suppress the transverse structure function $F_1$. We demonstrate that strong nuclear effects in $\sigma_A/\sigma_D$ and $R_A/R_D$, recently observed by HERMES Collaboration, can be explained in terms of the nuclear enhanced power corrections.Comment: Latex, 10 pages including 3 figure