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

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 $v_2$ 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 $v_2$ of ${\pi }^{\pm }$, $K^{\pm }$, $K_S^0$, $p$, and $\Lambda$ in Au+Au collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 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 $v_2$ for all hadrons studied provides evidence for the onset of dominant partonic interactions by $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 4.5 GeV.

arXiv comment8 pages, 4 figures

References in corpus (33)

• Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions
• Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration
• Glauber Modeling in High Energy Nuclear Collisions
• A Multi-Phase Transport Model for Relativistic Heavy Ion Collisions
• Methods for analyzing anisotropic flow in relativistic nuclear collisions
• Systematic Measurements of Identified Particle Spectra in pp, d+Au and Au+Au Collisions from STAR
• The phase diagram of dense QCD
• Hadron production in central nucleus-nucleus collisions at chemical freeze-out
• Comparison of Chemical Freeze-Out Criteria in Heavy-Ion Collisions
• Bulk Properties of the Medium Produced in Relativistic Heavy-Ion Collisions from the Beam Energy Scan Program
• Elliptic flow at large transverse momenta from quark coalescence
• Mapping the Phases of Quantum Chromodynamics with Beam Energy Scan
• Particle production and equilibrium properties within a new hadron transport approach for heavy-ion collisions
• Elliptic Flow: Transition from out-of-plane to in-plane Emission in Au + Au Collisions
• Inclusive charged hadron elliptic flow in Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 39 GeV
• Elliptic flow of identified hadrons in Au+Au collisions at $\sqrt{s_{NN}}=$ 7.7--62.4 GeV
• Cumulants and Correlation Functions of Net-proton, Proton and Antiproton Multiplicity Distributions in Au+Au Collisions at energies available at the BNL Relativistic Heavy Ion Collider
• Measurement of $D^0$ azimuthal anisotropy at mid-rapidity in Au+Au collisions at \sNN = 200\,GeV
• Properties of the QCD Matter -- An Experimental Review of Selected Results from RHIC BES Program
• Strange and Multi-strange Particle Production in Au+Au Collisions at $\sqrt{s_{NN}}$ = 62.4 GeV
• Observation of an energy-dependent difference in elliptic flow between particles and anti-particles in relativistic heavy ion collisions
• Directed, elliptic and higher order flow harmonics of protons, deuterons and tritons in Au+Au collisions at $\sqrt{s_{NN}}=2.4$ GeV
• Constituent quark scaling violation due to baryon number transport
• Centrality dependence of identified particle elliptic flow in relativistic heavy ion collisions at sqrt(s)= 7.7--62.4 GeV
• Centrality and transverse momentum dependence of elliptic flow of multi-strange hadrons and $\varphi$ meson in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV
• A Study of the Properties of the QCD Phase Diagram in High-Energy Nuclear Collisions
• The STAR Event Plane Detector
• Mean-field update in the JAM microscopic model: Mean-field effects on collective flow in high-energy heavy-ion collisions at $\sqrt{s_{NN}}=2-20$ GeV energies
• Event Anisotropy in High Energy Nucleus-Nucleus Collisions
• On the Origin of the Elliptic Flow and its Dependence on the Equation of State in Heavy Ion Reactions at Intermediate Energies
• Directed flow of $\Lambda$ in high-energy heavy-ion collisions and $\Lambda$ potential in dense nuclear matter
• Phase diagram determination at fivefold nuclear compression
• Anti-flow of Mesons in the High Baryon Density Region

Cited by in corpus (5)

• Bayesian Quantification of Observability and Equation of State of Twin Stars
• Bayesian Inference of Hybrid Star Properties from Future High-Precision Measurements of Their Radii
• Physics of Collectivity and EOS from the RHIC Beam Energy Scan Program
• Transport-model investigation of scaling of the number of constituent quarks and the hadronic-partonic transition in Au + Au collisions
• Elliptic flow of charged hadrons in d+Au collisions at $\sqrt{s_{NN}}=$ 200 GeV using a multi-phase transport model