Eur. Phys. J. A (2025) 61: 161
https://doi.org/10.1140/epja/s10050-025-01633-2

Regular Article - Theoretical Physics

Exploring freezeout dynamics and deconfinement in $Au+Au$ collisions using STAR data

¹ Department of Physics, Xinzhou Normal University, 034000, Xinzhou, China
² Hubei Key Laboratory of Energy Storage and Power Battery, School of Optoelectronic Engineering, Hubei University of Automotive Technology, 442002, Shiyan, China
³ Department of Physics, Abdul Wali Khan University Mardan, 23200, Mardan, Pakistan
⁴ College of Science, China Three Gorges University, 443002, Yichang, People’s Republic of China
⁵ Department of Computer Sciences, Faculty of Computing and Information Technology, Northern Border University, 91911, Rafha, Saudi Arabia
⁶ Department of Physics, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, 11671, Riyadh, Saudi Arabia
⁷ College of Humanities and Sciences, Ajman University, 346, Ajman, UAE

^a waqas_phy313@yahoo.com, 20220073@huat.edu.cn
^b ajaz@awkum.edu.pk

Received: 7 March 2025
Accepted: 27 June 2025
Published online: 14 July 2025

Abstract

The transverse momentum distribution of ${\pi }^{+}$, $K^{+}$, and p are analyzed in the most central Gold-Gold, $Au-Au$, collisions over a wide energy range by the Tsallis distribution with transverse flow velocity. Analysis has been done on the experimental data estimated by STAR Collaboration, which ranges from $\sqrt{s_{\mathit{NN}}}$ = 7.7 to 200 GeV. The freezeout parameters namely, the kinetic freezeout temperature, T, transverse flow velocity, ${\beta }_T$, and the non-extensive related parameter, $n_0$, are obtained. The kinetic freezeout temperature is common for all the particles. Besides, other parameters such as the initial temperature of emission sources, mean transverse momentum, and chemical freezeout temperature, $T_{\mathit{ch}}$, along with some thermodynamic quantities including the particle number density, n, squared sound speed, $c_s^2$, energy density, $\epsilon$, pressure, P, and entropy density, s, are extracted. We examine how each of these parameters behave in relation to energy. As the collision energy grows at the Relativistic Heavy Ion Collider (RHIC), the parameters $T_i$, $\epsilon$, n, P, and s, all rise steadily, however, at certain energies, the parameters T, ${\beta }_T$, $n_0$, $T_{\mathit{ch}}$, $⟨p_T⟩$, and $c_s^2$ reveals a pattern of compression. According to this saturation, the shift in phase for partial deconfinement and complete deconfinement have onset energies of 7.7 and 39 GeV, respectively. Furthermore, the distinction between the above three types of temperatures is investigated, and we found that their trends with fluctuating energy is not homogeneous. We also reveal the system’s evolution in $Au-Au$ collisions by showing that $T_i$ is larger than $T_{\mathit{ch}}$, and the latter is larger than T.