Leading Hadron Production in $d$+Au and $^3$He+Au collisions in the PHENIX experiment

TL;DR

This study measures neutral pion production in $^3$He+Au collisions at 200 GeV, compares nuclear modification factors with $d$+Au collisions, and explores system size effects on particle suppression and momentum loss.

Contribution

It provides new measurements of neutral pion production and nuclear modification factors in $^3$He+Au collisions, extending understanding of system size dependence in heavy-ion collisions.

Findings

$R_{AA}$ converges for $N_{part}>12$ across systems.

Clear ordering of $R_{dAu} > R_{HeAu} > R_{AuAu}$ for $N_{part}<12$.

Fractional momentum loss estimated for central $^3$He+Au collisions.

Abstract

Neutral pions have been measured in $^3$He+Au collisions at $\sqrt{s_{_{NN}}}$=200 GeV up to 20 GeV/$c$ in the RHIC Year-2014 run. The nuclear modification factor $R_{\rm AA}$ was measured and compared with that from $d$+Au collisions. The integrated $R_{\rm AA}$ as a function of $N_{\rm part}$ was calculated for $d$+Au, $^3$He+Au and Au+Au collisions at $\sqrt{s_{_{NN}}}$=200 GeV, and found to converge for $N_{\rm part}>$12, while a clear system ordering $R_{\rm dAu}$$>$$R_{\rm HeAu}$$>$$R_{\rm AuAu}$ was observed for $N_{\rm part}<$12. The fractional momentum loss for the most central $^3$He+Au collisions was also estimated.