Identified Particle Dependence of Nuclear Modification Factors in d+Au Collisions at RHIC
L. S. Barnby
TL;DR
The study uses d+Au collisions at $\sqrt{s_{NN}} = 200$ GeV to probe initial-state effects on hadron production by comparing to p+p spectra scaled by $\langle N_{binary} \rangle$, revealing a Cronin enhancement that persists at RHIC energies and shows hadron-species dependence. By measuring identified hadrons at mid-rapidity and unidentified hadrons at forward rapidity, the work explores centrality dependence and contrasts with Au+Au results to elucidate initial-state contributions and possible saturation phenomena. The findings provide constraints on the role of Cronin-type broadening and saturation models in small systems and guide interpretation of nuclear modification factors. The analysis demonstrates how forward-rapidity measurements can test predictions from saturation frameworks such as CGC.
Abstract
We present transverse momentum spectra from d+Au collisions at sqrt(s_NN) = 200 GeV for identified hadrons at mid-rapidity and unidentified hadrons in the forward rapidity region using the Solenoidal Tracker at RHIC. We scale these spectra by the mean number of binary collisions to form a transverse momentum dependent ratio to spectra from p+p collisions, showing that the Cronin effect measured at lower centre-of-mass energies is also present at this higher energy. The data also suggest a dependence of the Cronin effect on the hadron species. We also compare central d+Au collisions to more peripheral ones, contrasting the behaviour to that observed in Au+Au collisions and remark on unidentified hadrons at forward rapidities which show a qualitatively different behaviour.