Abstract

The pseudorapidity asymmetry and centrality dependence of charged hadron spectra in d+Au collisions at roots(NN)=200 GeV are presented. The charged particle density at midrapidity, its pseudorapidity asymmetry, and centrality dependence are reasonably reproduced by a multiphase transport model, by HIJING, and by the latest calculations in a saturation model. Ratios of transverse momentum spectra between backward and forward pseudorapidity are above unity for p(T) below 5 GeV/c. The ratio of central to peripheral spectra in d+Au collisions shows enhancement at 2(T)6 GeV/c, with a larger effect at backward rapidity than forward rapidity. Our measurements are in qualitative agreement with gluon saturation and in contrast to calculations based on incoherent multiple partonic scatterings.