Baryon-to-Meson ratios in jets from Au+Au and p+p collisions at √s_NN = 200 GeV

University of Illinois at Chicago, USA

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Published online: 17 April 2026

Abstract

Measurements at RHIC and the LHC show strongly enhanced baryon-to-meson yield ratios at intermediate transverse momenta (p_T) in high-energy nuclear collisions compared to a p+p baseline. This enhancement is attributed to strong hydrodynamic flow and parton recombination in the Quark-Gluon Plasma (QGP). Jet probes have been used extensively to gain insights into QGP properties, with substantial modifications to jet yields and internal structures seen across multiple measurements. Despite apparent medium-induced changes to jet fragmentation patterns, the LHC results indicate that in-jet baryon-to-meson ratios remain similar to that of p+p measurements and are significantly different from that of the QGP bulk. To explore this behavior at RHIC, we employ jet-hadron correlation and particle identification to measure in-jet proton-to-pion yield ratios for p_T < 5.0 GeV/c. We present the first in-cone baryon-to-meson yield ratios associated with fully reconstructed jets from Au+Au and p+p collisions at √s_NN = 200 GeV using the STAR detector at RHIC. The measured in-jet ratios are similar between the two systems for our selected kinematic regime, despite significant difference between the inclusive ratios for the same systems.