Yuri V. Kovchegov

Unitarization of the BFKL Pomeron on a nucleus

We analyze the evolution equation describing all multiple hard Pomeron exchanges in hadronic or nuclear structure functions that was proposed earlier in Phys. Rev. D 60, 034008 (1999). We construct a perturbation series providing us with an exact solution to the equation outside of the saturation region. The series demonstrates how at moderately high energies the corrections to the single BFKL Pomeron exchange contribution, which are due to the multiple Pomeron exchanges, start unitarizing the total deep inelastic scattering cross section. We show that as the energy increases the scattering cross section of the quark-antiquark pair of a fixed transverse separation on a hadron or nucleus given by the solution of our equation inside of the saturation region unitarizes and becomes independent of energy. The corresponding F{sub 2} structure function also unitarizes and becomes linearly proportional to ln s. We also discuss possible applications of the developed technique to diffraction. (c) 2000 The American Physical Society.

Saturation physics and deuteron-Gold collisions at RHIC

Abstract We present a review of parton saturation/Color Glass Condensate physics in the context of deuteron–gold ( d + Au ) collisions at RHIC. Color Glass Condensate physics is a universal description of all high energy hadronic and nuclear interactions. It comprises classical (McLerran–Venugopalan model and Glauber–Mueller rescatterings) and quantum evolution (JIMWLK and BK equations) effects both in small- x hadronic and nuclear wave functions and in the high energy scattering processes. Proton–nucleus (or d + A ) collisions present a unique opportunity to study Color Glass Condensate predictions, since many relevant observables in proton–nucleus collisions are reasonably well-understood theoretically in the Color Glass Condensate approach. In this article we review the basics of saturation/Color Glass Condensate physics and reproduce derivations of many important observables in proton (deuteron)–nucleus collisions. We compare the predictions of Color Glass physics to the data generated by d + Au experiments at RHIC and observe an agreement between the data and the theory, indicating that Color Glass Condensate has probably been discovered at RHIC. We point out further experimental measurements which need to be carried out to test the discovery.

Cronin effect and high p(T) suppression in pA collisions

We review the predictions of the theory of a color glass condensate for a gluon production cross section in

Inclusive gluon production in DIS at high parton density

p(d)A

Triumvirate of running couplings in small-x evolution

collisions. We demonstrate that, at moderate energies, when the gluon production cross section can be calculated in the framework of the McLerran-Venugopalan model, it has only a partonic level Cronin effect in it. At higher energies or rapidities corresponding to smaller values of the Bjorken x, quantum evolution becomes important. The effect of quantum evolution at higher energies or rapidities is to introduce the suppression of high-

Nuclear modification factor in d + Au collisions: onset of suppression in the color glass condensate

{p}_{T}

AdS/CFT applications to relativistic heavy-ion collisions: a brief review

gluons slightly decreasing the Cronin enhancement. At still higher energies or rapidities quantum evolution leads to the suppression of produced gluons at all values of

Modeling heavy ion collisions in AdS/CFT

{p}_{T}.

Subleading-Nc corrections in non-linear small-x evolution

We calculate the cross section of a single inclusive gluon production in deep inelastic scattering at very high energies in the saturation regime, where the parton densities inside hadrons and nuclei are large and the evolution of structure functions with energy is nonlinear. The expression we obtain for the inclusive gluon production cross section is generated by this nonlinear evolution. We analyze the rapidity distribution of the produced gluons as well as their transverse momentum spectrum given by the derived expression for the inclusive cross section. We propose an ansatz for the multiplicity distribution of gluons produced in nuclear collisions which includes the effects of nonlinear evolution in both colliding nuclei.