  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.
