Particle-species dependent modification of jet-induced correlations in Au+Au collisions at sqrt(s_NN) = 200 GeV

TL;DR

This study measures how jet-induced particle correlations in gold-gold collisions at high energy are modified by the medium, revealing centrality-dependent changes in baryon and meson production that suggest recombination effects.

Contribution

It provides the first detailed analysis of baryon and meson correlations at intermediate and low transverse momentum in heavy-ion collisions, highlighting medium-induced modifications.

Findings

Jet correlations are strongly modified in central collisions.

Baryon-to-meson ratio increases with centrality and pT, reaching values similar to inclusive measurements.

Results suggest recombination of soft partons as a possible explanation.

Abstract

We report PHENIX measurements of the correlation of a trigger hadron at intermediate transverse momentum (2.5<p_{T,trig}<4 GeV/c), with associated mesons or baryons at lower p_{T,assoc}, in Au+Au collisions at sqrt(s_NN) = 200 GeV. The jet correlations for both baryons and mesons show similar shape alterations as a function of centrality, characteristic of strong modification of the away-side jet. The ratio of jet-associated baryons to mesons for this jet increases with centrality and p_{T,assoc} and, in the most central collisions, reaches a value similar to that for inclusive measurements. This trend is incompatible with in-vacuum fragmentation, but could be due to jet-like contributions from correlated soft partons which recombine upon hadronization.