Near-side azimuthal and pseudorapidity correlations using neutral strange baryons and mesons in d+Au, Cu+Cu and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

TL;DR

This study measures near-side di-hadron correlations involving neutral strange baryons and mesons in various heavy-ion collisions at 200 GeV to explore flavor and baryon/meson dependence of jet-like correlations.

Contribution

It provides the first detailed analysis of neutral strange particle correlations in different collision systems, revealing discrepancies with PYTHIA predictions for particle composition.

Findings

Jet-like correlations show a narrow peak in azimuth and pseudorapidity.

Strange particle composition in jet-like correlations differs from PYTHIA predictions.

Unidentified particle yields are well modeled by PYTHIA, unlike strange particle composition.

Abstract

We present measurements of the near-side of triggered di-hadron correlations using neutral strange baryons ($\Lambda$, $\bar{\Lambda}$) and mesons ($K^0_S$) at intermediate transverse momentum (3 $<$ $p_T$ $<$ 6 GeV/$c$) to look for possible flavor and baryon/meson dependence. This study is performed in $d$+Au, Cu+Cu and Au+Au collisions at $\sqrt{s_{{NN}}}$ = 200 GeV measured by the STAR experiment at RHIC. The near-side di-hadron correlation contains two structures, a peak which is narrow in azimuth and pseudorapidity consistent with correlations due to jet fragmentation, and a correlation in azimuth which is broad in pseudorapidity. The particle composition of the jet-like correlation is determined using identified associated particles. The dependence of the conditional yield of the jet-like correlation on the trigger particle momentum, associated particle momentum, and centrality for correlations with unidentified trigger particles are presented. The neutral strange particle composition in jet-like correlations with unidentified charged particle triggers is not well described by PYTHIA. However, the yield of unidentified particles in jet-like correlations with neutral strange particle triggers is described reasonably well by the same model.