Exploring freezeout dynamics and deconfinement in \(Au+Au\) collisions using STAR data

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 \(\sqrt{s_{NN}}\) = 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, \(T_{ch}\), along with some thermodynamic quantities including the particle number density, n, squared sound speed, \(c^2_s\), energy density, \(\varepsilon \), 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 \(T_i\), \(\varepsilon \), n, P, and s, all rise steadily, however, at certain energies, the parameters T, \(\beta _T\), \(n_0\), \(T_{ch}\), \( \langle p_T \rangle \), and \(c^2_s\) 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 \(T_{ch}\), and the latter is larger than T.