Baryon-to-Meson Ratios in Jets from Au+Au and p+p Collisions at √sNN = 200 GeV

University of Illinois at Chicago, 845 W Taylor St, Chicago, IL, USA

^* e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 5 November 2025

Abstract

Measurements at RHIC and the LHC show strongly enhanced inclusive hadron baryon-to-meson yield ratios at intermediate transverse momenta (p_T) in high-energy nuclear collisions compared to 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 mediuminduced 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 with the STAR detector at RHIC, we employ jet-hadron correlation and particle identification to measure in-cone baryon-to-meson yield ratios associated with fully reconstructed jets from Au+Au and p+p collisions at √sNN = 200 GeV. These in-jet ratios are studied as a function of jet radii, R = 0.2, 0.3, 0.4, with a jet constituent p_T selection of p_T^const > 2.0 GeV / c. Varying the jet radius allows us to probe jets with different levels of QGP interaction. The in-jet baryon-tomeson ratios are compared between Au+Au and p+p to examine what effect the presence of QGP has on the hadronization process in jets.