Energy Dependence of the Cronin Effect from Nonlinear QCD Evolution

The nonlinear evolution of dense partonic systems has been suggested as a novel physics mechanism relevant for the dynamics of $p\mathrm{\text{−}}A$ and $A\mathrm{\text{−}}A$ collisions at collider energies. Here we study to what extent the description of Cronin enhancement in the framework of this nonlinear evolution is consistent with the recent observation in $\sqrt{s}=200\mathrm{G}\mathrm{e}\mathrm{V}$ $d\mathrm{\text{−}}\mathrm{A}\mathrm{u}$ collisions at the Relativistic Heavy Ion Collider. We solve the Balitsky-Kovchegov evolution equation numerically for several initial conditions encoding Cronin enhancement. We find that the properly normalized nuclear gluon distribution is suppressed at all momenta relative to that of a single nucleon. For the resulting spectrum of produced gluons in $p\mathrm{\text{−}}A$ and $A\mathrm{\text{−}}A$ collisions, the nonlinear QCD evolution is unable to generate a Cronin-type enhancement, and it quickly erases any such enhancement which may be present at lower energies.