Centrality and System Size Dependence among Freezeout Parameters and the Implications for EOS and QGP in High-Energy Collisions

Muhammad Waqas; Abd Haj Ismail; Haifa I Alrebdi; Muhammad Ajaz

doi:10.3390/e25121586

Centrality and System Size Dependence among Freezeout Parameters and the Implications for EOS and QGP in High-Energy Collisions

Entropy (Basel). 2023 Nov 26;25(12):1586. doi: 10.3390/e25121586.

Authors

Muhammad Waqas¹, Abd Haj Ismail², Haifa I Alrebdi³, Muhammad Ajaz⁴

Affiliations

¹ School of Mathematics, Physics and Optoelectronic Engineering, Hubei University of Automotive Technology, Shiyan 442002, China.
² College of Humanities and Sciences, Ajman University, Ajman P.O. Box 346, United Arab Emirates.
³ Department of Physics, College of Science, Prince Nourah Bint Abdulrahman Univeristy, P.O.Box 84428, Riyadh 11671, Saudi Arabia.
⁴ Department of Physics, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan.

Abstract

Utilizing the Modified Hagedorn function with embedded flow, we analyze the transverse momenta (pT) and transverse mass (mT) spectra of π+ in Au-Au, Cu-Cu, and d-Au collisions at sNN = 200 GeV across various centrality bins. Our study reveals the centrality and system size dependence of key freezeout parameters, including kinetic freezeout temperature (T0), transverse flow velocity (βT), entropy-related parameter (n), and kinetic freezeout volume (V). Specifically, T0 and n increase from central to peripheral collisions, while βT and V show the opposite trend. These parameters also exhibit system size dependence; T0 and βT are smaller in larger collision systems, whereas V is larger. Importantly, central collisions correspond to a stiffer Equation of State (EOS), characterized by larger βT and smaller T0, while peripheral collisions indicate a softer EOS. These insights are crucial for understanding the properties of Quark-Gluon Plasma (QGP) and offer valuable constraints for Quantum Chromodynamics (QCD) models at high temperatures and densities.

Keywords: EOS; QGP; freezeout parameters; non-extensivity; qauntum chromodynamics.

Grants and funding

This work is supported by the Hubei University of Automotive Technology Doctoral Research Fund under Grant Number BK202313 and and Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2023R106), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia. We also acknowledge Ajman University, Internal Research Grant No. [DRGS Ref. 2023-IRG-HBS-13] for supporting the research project.