Forward Production in d+Au Collisions by Parton Recombination

Abstract

Hadron production at forward rapidities in d+Au collisions is studied in the framework of parton recombination in the final state. Multiple scattering and gluon saturation in the initial state are not explicitly considered. The recombination of soft and shower partons is found to be important. The soft parton densities are determined by extrapolation from the parametrization fixed at \eta=0 with no unconstrained adjustments. The suppression of R_{CP} observed at high \eta is understood as the simple consequence of the reduction of the soft parton density on the deuteron side compared to that on the gold side. The effect of momentum degradation responsible for baryon stopping is also considered. The asymmetry of backward-to-forward spectra can be reproduced within the same framework without any change in the basic physics.

Comments: 23 pages in LaTeX + 8 figures in eps. No quantitative changes from the previous version, only some general statements are expanded