Rapidity and species dependence of particle production at large transverse momentum for d+Au collisions at s(NN)**(1/2) = 200-GeV
Phys.Rev.C 76 (2007) 054903, 2007.
The STAR collaboration

Abstract (data abstract)
We determine rapidity asymmetry in the production of charged pions, protons, and antiprotons for large transverse momentum ($p_{T}$) for $d+Au$ collisions at $\sqrt{s_{NN}}=200$ GeV. The rapidity asymmetry is defined as the ratio of particle yields at backward rapidity ($Au$ beam direction) to those at forward rapidity ($d$ beam direction). The identified hadrons are measured in the rapidity regions $|y| < 0.5$ and $0.5 < |y| < 1.0$ for the $p_{T}$ range $2.5 < p_{T} < 10$ GeV/c. We observe significant rapidity asymmetry for charged pion and proton + antiproton production in both the rapidity regions. The asymmetry is larger for $0.5 < |y| < 1.0$ than for $|y| < 0.5$ and is almost independent of particle type. The measurements are compared to various model predictions employing multiple scattering, energy loss, nuclear shadowing, saturation effects, and recombination and also to a phenomenological parton model. We find that asymmetries are sensitive to model parameters and show model preference. The rapidity dependence of $\pi^{-} / \pi^{+}$ and $\bar{p} / p$ ratios in peripheral $d+Au$ and forward neutron-tagged events are used to study the contributions of valence quarks and gluons to particle production at high $p_{T}$.

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