Parton Ladder Splitting and the Rapidity Dependence of Transverse Momentum Spectra in Deuteron-Gold Collisions at RHIC

Abstract

We present a phenomenological approach (EPOS), based on the parton model, but going much beyond, and try to understand proton-proton and deuteron-gold collisions, in particular the transverse momentum results from all the four RHIC experiments. It turns out that elastic and inelastic parton ladder splitting is the key issue. Elastic splitting is in fact related to screening and saturation, but much more important is the inelastic contribution, being crucial to understand the data. We investigate in detail the rapidity dependence of nuclear effects, which is actually relatively weak in the model, in perfect agreement with the data, if the latter ones are interpreted correctly.Comment: 39 pages, 28 figure