Onset of Constituent Quark Number Scaling in Heavy-Ion Collisions at RHIC

2025/04/02 by STAR Collaboration, Aboona, B. E., Adam, J. +355 · 1 citation
#14J26 (Secondary) #14J60 (Primary) 14F05 #F.2.2 #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #I.2.7 #Nuclear Experiment (nucl-ex)

paper · doi:10.48550/arxiv.2504.02531

Abstract

Partonic collectivity is one of the necessary signatures for the formation of quark-gluon plasma in high-energy nuclear collisions. Number of constituent quarks (NCQ) scaling has been observed for hadron elliptic flow v₂ in top energy nuclear collisions at the Relativistic Heavy Ion Collider and the LHC, and this has been theoretically suggested as strong evidence for partonic collectivity. In this Letter, a systematic analysis of v₂ of π^±, K^±, K⁰_S, p, and Λ in Au+Au collisions at √s__\rmNN = 3.2, 3.5, 3.9, and 4.5 GeV, with the STAR experiment at the Relativistic Heavy Ion Collider, is presented. NCQ scaling is markedly violated at 3.2 GeV, consistent with a hadronic-interaction dominated equation of state. However, as the collision energy increases, a gradual evolution to NCQ scaling is observed. This beam-energy dependence of v₂ for all hadrons studied provides evidence for the onset of dominant partonic interactions by √s__\rmNN = 4.5 GeV.

Cited by

• Bayesian Quantification of Observability and Equation of State of Twin Stars

Related

• Observation of partonic collectivity via p_{\rm T}-differential radial flow fluctuations in Au+Au collisions at √s_{\rm NN} = 200 GeV
• Some insights on the partonic collectivity in heavy-ion collisions
• Transport-model investigation of scaling of the number of constituent quarks and the hadronic-partonic transition in Au + Au collisions
• Violation of NCQ scaling in hadron elliptic flow in Au+Au collisions at √s_NN=3.0-7.7GeV
• Energy dependence of ϕ-meson production and elliptic flow in Au+Au collisions at STAR