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 σ dif f /σ tot and predict the x IP and β behavior of the nuclear diffractive structure function F2,A2 , which probes the nuclear dependence of the structure of the Pomeron. We show that saturation physics predicts that approximately 37 % of the events observed at eRHIC should be diffractive.

One of the frontiers of QCD which are intensely investigated in high energy experiments is the high energy (small x) regime, where we expect to observe the non-linear behavior of the theory. In this regime, the growth of the parton distribution should saturate, forming a Color Glass Condensate (CGC). In fact, signals of parton saturation have already been observed both in ep deep inelastic scattering at HERA and in deuteron-gold collisions at RHIC. Currently, a global description of the existing experimental data is possible considering different phenomenological saturation models for the two processes within the CGC formalism. In this letter we analyze the universality of these dipole cross section parameterizations and verify that they are not able to describe the HERA and RHIC data simultaneously. We analyze possible improvements in the parameterizations and propose a new parametrization for the forward dipole amplitude which allows us to describe quite well the small-x ep HERA data on F 2 structure function as well as the dAu RHIC data on charged hadron spectra. It is an important signature of the universality of the saturation physics.

Perturbative QCD predicts that the growth of the gluon density at high energies should saturate, forming a Color Glass Condensate (CGC), which is described in mean field approximation by the Balitsky-Kovchegov (BK) equation. In this paper we study the γγ interactions at high energies and estimate the main observables which will be probed at future linear colliders using the color dipole picture. We discuss in detail the dipole -dipole cross section and propose a new relation between this quantity and the dipole scattering amplitude. The total γγ, γ * γ * cross-sections and the real photon structure function F γ 2 (x, Q 2 ) are calculated using the recent solution of the BK equation with running coupling constant and the predictions are compared with those obtained using phenomenological models for the dipole-dipole cross section and scattering amplitude. We demonstrate that these models are able to describe the LEP data at high energies, but predict a very different behavior for the observables at higher energies. Therefore we conclude that the study of γγ interactions can be useful to constrain the QCD dynamics.

Perturbative Quantum Chromodynamics (pQCD) predicts that the small-x gluons in a hadron wavefunction should form a Color Glass Condensate (CGC), characterized by a saturation scale Q s (x, A) which is energy and atomic number dependent. In this paper we study the predictions of CGC physics for electron -ion collisions at high energies. We consider that the nucleus at high energies acts as an amplifier of the physics of high parton densities and estimate the nuclear structure function F A 2 (x, Q 2 ), as well as the longitudinal and charm contributions, using a generalization for nuclear targets of the Iancu-Itakura-Munier model which describes the ep HERA data quite well. Moreover, we investigate the behavior of the logarithmic slopes of the total and longitudinal structure functions in the kinematical region of the future electron -ion collider eRHIC.In the high energy limit, perturbative Quantum Chromodynamics (pQCD) predicts that the small-x gluons in a hadron wavefunction should form a Color Glass Condensate (CGC), which is described by an infinite hierarchy of coupled evolution equations for the correlators of Wilson lines [1,2,3,4]. In the absence of correlations, the first equation in the Balitsky-JIMWLK hierarchy decouples and is then equivalent to the equation derived independently by Kovchegov within the dipole formalism [5]. The Balitsky-Kovchegov (BK) equation describes the energy evolution of the dipole-target scattering amplitude N (x, r). Although a complete analytical solution is still lacking, its main properties are known (for recent reviews see, e.g. [6,7,8,9]): (a) for the interaction of a small dipole (r ≪ 1/Q s ), N (r) ≈ r 2 , implying that this system is weakly interacting; (b) for a large dipole (r ≫ 1/Q s ), the system is strongly absorbed and therefore N (r) ≈ 1. This property is associated to the large density of saturated gluons in the hadron wave function. Furthermore, several groups have studied the numerical solution of the BK equation [10,11,12] and confirmed many of the theoretical predictions. In particular, the studies presented in [11,12] have demonstrated that the BK solution for fixed constant coupling preserves the atomic number dependence of the saturation scale present in the initial condition, while for running α s this dependence is reduced with increasing rapidity, as predicted by Mueller in Ref. [13].The search for signatures of parton saturation effects has been an active subject of research in the last years (for recent reviews see, e.g. [6,9,14]). On one hand, it has been observed that the HERA data at small x and low Q 2 can be successfully described with the help of saturation models [15,16,17,18,19], with the experimental results for the total cross section [20] and inclusive charm production [21] presenting the property of geometric scaling. On the other hand, the recently observed [22] suppression of high p T hadron yields at forward rapidities in dAu collisions at RHIC has the behavior anticipated on the basis of CGC ideas [23,24,25,26]. All these results pro...

We calculate the nuclear cross section for coherent and incoherent vector meson production within the QCD color dipole picture, including saturation effects. Theoretical estimates for scattering on both light and heavy nuclei are given over a wide range of energy.