The measurements of the centrality dependence of $dN/d\eta$ and transverse momentum spectra from mid- to forward rapidity in d+Au collisions at $\sqrt{ s_{ _{ \rm NN}}} =$ 200 GeV are reported. They provide a sensitive tool for understanding the dynamics of multi-particle production in the high parton-density regime. In particular, we observe strong suppression of the nuclear modification factor $R_{ CP}$ at forward rapidities (d-side, $\eta$ = 3.1) and enhancement at backward rapidity ($\eta$ = $-$3.1). An empirical scaling is obtained for multiplicity and $R_{ CP}$ when a shift of the center-of-mass in the asymmetric d+Au collisions with respect to the nucleon-nucleon system is applied.
Categories: nucl-ex