Saturation physics meets RHIC data

We review the derivation of the expression for the cross section of single inclusive gluon production in proton-nucleus collisions (pA) and in deep inelastic scattering (DIS) at very high energy, when the parton saturation/Color Glass Condensate effects become important in the target's wave function, both at the classical and quantum levels. We study the resulting particle spectra concentrating on the nuclear modification factor R-pA for gluon production. We show that at moderately high energy/rapidity the nuclear modification factor R-pA exhibits Cronin enhancement at transverse momenta P-T of the order of the saturation scale Q(s). As the energy/rapidity increases, R-pA decreases. At sufficiently high energy/rapidity R-pA becomes less than 1 for all values Of p(T) indicating the onset of suppression of gluon production due to small-x evolution effects. Our prediction of suppression is confirmed by the recently reported BRAHMS collaboration data on particle production at forward rapidity in dAu collisions at RHIC.