Hadron production in the forward and backward rapidities in dAu collisions at RHIC

TL;DR

The paper addresses cold nuclear matter effects on hadron production in d+Au collisions at RHIC by extending R_CP measurements to forward and backward rapidities using novel hadron identification via the PHENIX muon spectrometers. It presents methods to isolate hadrons from light-meson decays and punch-through hadrons, with centrality and pT dependent results. The findings show a suppression at forward rapidity and an enhancement at backward rapidity, consistent with small-x shadowing or saturation and large-x Cronin/antishadowing effects in Au, respectively. These results help disentangle initial- from final-state effects and motivate future R_dA measurements and open charm/Drell-Yan studies for a complete understanding of nuclear modifications.

Abstract

We have developed new techniques to detect hadrons with the PHENIX muon spectrometers. This allows us to study the centrality dependent nuclear modification factor $R_{CP}$ with high $p_{T}$ hadrons in both forward (d direction) and backward (Au direction) rapidities, $1 < |η| < 2$, in dAu collisions at $\sqrt{s_{NN}} = 200 GeV$. Preliminary results show a suppression (enhancement) of high $p_{T}$ hadron production in central $0-20%$ dAu collisions relative to the peripheral one ($60-88%$ in centrality) at forward (backward) rapidity.

Figures (4)

• Figure 1: Normalized collision vertex distribution from events with forward muons($p_Z > 0$).
• Figure 2: Momentum distributions of tracks stopped at various muID absorber layers.
• Figure 3: $R_{CP}$ measured with muons from light meson decays.
• Figure 4: $R_{CP}$ from punch-through hadrons.