Probing Parton Dynamics of QCD Matter with $\Omega$ and $\varphi$ Production

Abstract

We present measurements of $\Omega$ and $\varphi$ production at mid-rapidity from Au+Au collisions at nucleon-nucleon center-of-mass energies $\sqrt{s_{NN}}$ = 7.7, 11.5, 19.6, 27 and 39 GeV by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). Motivated by the coalescence formation mechanism for these strange hadrons, we study the ratios of $N({\Omega }^{-}+{\Omega }^{+})/(2N(\varphi ))$. These ratios as a function of transverse momentum ($p_T$) fall on a consistent trend at high collision energies, but start to show deviations in peripheral collisions at $\sqrt{s_{NN}}$ = 19.6, 27 and 39 GeV, and in central collisions at 11.5 GeV in the intermediate $p_T$ region of 2.4-3.6 GeV/c. We further evaluate empirically the strange quark $p_T$ distributions at hadronization by studying the $\Omega /\varphi$ ratios scaled by the number of constituent quarks. The NCQ-scaled $\Omega /\varphi$ ratios show a suppression of strange quark production in central collisions at 11.5 GeV compared to $\sqrt{s_{NN}}>=19.6$ GeV. The shapes of the presumably thermal strange quark distributions in 0-60% most central collisions at 7.7 GeV show significant deviations from those in 0-10% most central collisions at higher energies. These features suggest that there is likely a change of the underlying strange quark dynamics in the transition from quark-matter to hadronic matter at collision energies below 19.6 GeV.

7 pages, 5 figures

References in corpus (10)

• The order of the quantum chromodynamics transition predicted by the standard model of particle physics
• QCD at finite chemical potential with six time slices
• Canonical partition function and finite density phase transition in lattice QCD
• Partonic flow and $\varphi$-meson production in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV
• Inclusive charged hadron elliptic flow in Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 39 GeV
• Energy dependence of phi meson production in central Pb+Pb collisions at sqrt(s_nn) = 6 to 17 GeV
• Measurements of $\varphi$ meson production in relativistic heavy-ion collisions at RHIC
• Mass ordering of differential elliptic flow and its violation for phi mesons
• Parton Distributions at Hadronization from Bulk Dense Matter Produced at RHIC
• Breaking of the number-of-constituent-quark scaling for identified-particle elliptic flow as a signal of phase change in low-energy data taken at the BNL Relativistic Heavy Ion Collider (RHIC)

Cited by in corpus (35)

• Properties of the QCD Matter -- An Experimental Review of Selected Results from RHIC BES Program
• Strange hadron production in Au+Au collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 7.7, 11.5, 19.6, 27, and 39 GeV
• Investigating the collision energy dependence of $\eta$/s in RHIC beam energy scan using Bayesian statistics
• Bulk Properties of the System Formed in Au+Au Collisions at $\sqrt{s_{\mathrm{NN}}}$ = 14.5 GeV
• Production of K${}^{\ast }(892{)}^0$ and $\varphi (1020)$ in pp and Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Enhanced production of strange baryons in high energy nuclear collisions from a multiphase transport model
• Quark number scaling of hadronic $p_T$ spectra and constituent quark degree of freedom in $p$-Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV
• Energy dependence study of directed flow in Au+Au collisions using an improved coalescence in AMPT model
• Excitation functions of parameters in Erlang distribution, Schwinger mechanism, and Tsallis statistics in RHIC BES program
• Analyzing transverse momentum spectra by a new method in high-energy collisions
• Production of light flavor and single-charmed hadrons in $pp$ collisions at $\sqrt{s}=5.02$ TeV in an equal-velocity quark combination model
• Quark number scaling of $p_T$ spectra for $\Omega$ and $\varphi$ in relativistic heavy-ion collisions
• Probing QCD critical fluctuations from the yield ratio of strange hadrons in relativistic heavy-ion collisions
• Elliptic flow of hadrons in equal-velocity quark combination mechanism in relativistic heavy-ion collisions
• ${\mathrm{K}}^{\ast }(892{)}^0$ and $\varphi (1020)$ production in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV
• Strange hadron production in a quark combination model in Au+Au collisions at RHIC energies
• Nucleon-number scalings of anisotropic flows and nuclear modification factor for light nuclei in the squeeze-out region
• Revealing the collision energy dependence of $\eta /s$ in RHIC-BES Au+Au collisions using Bayesian statistics
• Scaling of nuclear modification factors for hadrons and light nuclei
• Collective Excitation in High-Energy Nuclear Collisions -- In Memory of Professor Lianshou Liu
• Phenomenological Implications of the $p_T$ Spectra of $\varphi$ and $\Omega$ produced at LHC and RHIC
• Strangeness in STAR at RHIC
• Evidence of Coalescence Sum Rule in Elliptic Flow of Identified Particles in High-energy Heavy-ion Collisions
• Extracting strange quark freeze-out information in Pb+Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV from $\varphi$ and $\Omega$ production
• Constraining input parameters of AMPT model with $\varphi$ meson production
• Squeezed back-to-back correlations of bosons with nonzero widths in relativistic heavy-ion collisions
• Study of strange quark density fluctuations in Au+Au Collisions at $\sqrt{s_{NN}}$ = 7.7-200 GeV from AMPT Model
• Violation of NCQ scaling in hadron elliptic flow in Au+Au collisions at $\sqrt{s_{NN}}=3.0-7.7GeV
• Probing Late-Stage Hadronic Interactions at High Baryon Density via $K^{\ast 0}$ Production in the RHIC Beam Energy Scan Program
• Production of Strange and Charm Hadrons in Pb+Pb Collisions at $\sqrt{s_{NN}}=$ 5.02 TeV
• An appropriate statistical approach for nonequilibrium particle production
• Probing the tricritical endpoint of QCD phase diagram at NICA-FAIR energies
• Practical Considerations for Measuring Global Spin Density Matrix Elements of Vector Mesons in Heavy-Ion Collisions
• Cross sections for inelastic $K$+$\varphi$ scattering
• Insight from the elliptic flow of identified hadrons measured in relativistic heavy-ion collisions