In this contribution we estimate the influence of the shadowing effect and initial state parton energy loss in the quarkonium production at HERA-B. We analyze the xF behavior of the effective exponent alpha(xF) and present a comparison with the preliminary HERA-B data for J/psi production. Moreover, we present our predictions for <FONT FACE=Symbol>¡</FONT> production at HERA-B. The magnitude of these effects in the J/psi production at RHIC is also analyzed.

The discovery of the jet quenching in central Au + Au collisions at the Relativistic Heavy-ion Collider (RHIC) has provided clear evidence for the formation of strongly interacting dense matter. It has been predicted to occur due to the energy loss of high energy partons that propagate through the quark gluon plasma. Since the medium is not static and it cools while expands, the strong coupling is not fixed, running with the evolution of the system. In this work, we present an investigation of the dependence on the value of the strong coupling in the parton energy loss due to elastic scatterings in a parton plasma. We analyze different prescriptions for the QCD coupling and calculate the energy and length dependence of the fractional energy loss. Moreover, the quenching factor for light and heavy quarks is estimated. We found that the predicted enhancement of heavy to light hadrons (D/pi) ratio is strongly dependent on the running of the QCD coupling constant.

In this contribution we study the photoproduction of heavy quarks in coherent proton-nucleus (pA) and nucleus-nucleus (AA) interactions for RHIC and LHC energies and analyze if this process can be used to determine the QCD dynamics at high energies. The integrated cross section and rapidity distribution are estimated. Our results indicate that the nonlinear dynamics can be proven in those reactions, which are well suited for studing saturation effects.

In this paper we investigate the saturation physics in diffractive deep inelastic electron-ion scattering. We estimate the energy and nuclear dependence of the ratio sigmadiff/sigmatot. We show that saturation physics predicts that up to 37 % of the events observed at eRHIC should be diffractive. We have also studied how our results depend on the prescription to extend the saturation scale to the nuclear case.

We study the predictions of CGC physics for electron-ion collisions at high energies. The nucleus at high energies acts as an amplifier of saturation effects. We have investigated some observables, using a generalization for nuclear targets of the Iancu-Itakura-Munier model, and our results indicate that the experimental analysis of these observables in the future electron-ion collider could discriminate between linear and saturation physics, as well as constrain the behavior of the saturation scale.

In this work we use the IGM, a model that describes well the energy flux in hadronic collisions, to study the leading particle spectrum when saturation effects on the gluon distribution function are included. The leading particle spectrum is calculated for several center of mass energies (<FONT FACE=Symbol>Ö</FONT>s). In the very high energy limit we compare our results with the predictions made in a recent paper, which also addresses the same problem.

The high parton density regime of Quantum Chromodynamics (QCD) is briefly discussed. Some phenomenological aspects of saturation are described, mainly focusing on possible signatures of the non-linear QCD dynamics in electron-proton/nucleus collisions. Implications of these effects in central and ultraperipheral heavy-ion collisions are also presented.