Systematics of Kinetic Freeze-out Properties in High Energy Collisions from STAR

Abstract

The main aim of the RHIC Beam Energy Scan (BES) program is to explore the QCD phase diagram which includes search for a possible QCD critical point and the phase boundary between QGP and hadronic phase. We report the collision energy and centrality dependence of kinetic freeze-out properties from the measured mid-rapidity ($|y|<0.1)$ light hadrons (pions, kaons, protons and their anti-particles) for Au+Au collisions at the center-of-mass energy $\sqrt{s_{NN}}=$ 7.7, 11.5, 19.6, 27, and 39 GeV. The STAR detector, with a large uniform acceptance and excellent particle identification is used in the data collection and analysis. The kinetic freeze-out temperature $T_{\mathrm{kin}}$ and average collective velocity $⟨\beta ⟩$ parameters are extracted from blast-wave fits to the identified hadron spectra and systematically compared with the results from other collision energies including those at AGS, SPS and LHC. It is found that all results fall into an anti-correlation band in the 2-dimension ($T_{\mathrm{kin}}$, $⟨\beta ⟩$) distribution: the largest value of collective velocity and lowest temperature is reached in the most central collisions at the highest collision energy. The energy dependence of these freeze-out parameters are discussed.

4 pages, 5 figures. Contributed talk to appear as proceedings of Quark Matter 2014 conference held in Darmstadt, Germany during May 19-24, 2014

References in corpus (4)

• The order of the quantum chromodynamics transition predicted by the standard model of particle physics
• Systematic Measurements of Identified Particle Spectra in pp, d+Au and Au+Au Collisions from STAR
• Scale for the Phase Diagram of Quantum Chromodynamics
• Canonical partition function and finite density phase transition in lattice QCD

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• Multiplicity dependence of the freezeout parameters in high energy hadron-hadron collisions
• Formation of light nuclei at chemical freezeout: Description within a statistical thermal model
• Extracting Kinetic Freeze-out Properties in High Energy Collisions Using a Multi-source Thermal Model
• Kinetic freeze-out temperature and transverse flow velocity in Au-Au collisions at RHIC-BES energies
• Analysis of kinetic freeze out temperature and transverse flow velocity in nucleus-nucleus and proton-proton collisions at same center of mass energy
• Extracting temperature and transverse flow by fitting transverse mass spectra and HBT radii together
• Chemical freeze-out systematics of thermal model analysis using hadron yield ratios