الفهرس 
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Abstract
Thermal models have been successful in describing particle yields at various beam energies, including heavy ion collisions and others, as well as under the influence of the magnetic field. These models have been assumed the formation of a system in thermal and chemical equilibrium in the hadronic phase, with a set of thermody- namic variables for the hadronic phase, the most important of which are the chemical freeze-out temperature and baryon chemical potential. The transverse momentum spectrum of hadrons is believed to be a result of hot matter flowing in a transverse direction. The transverse momentum spectrum of hadrons has been measured for various identified particle species in (Nucleus–Nucleus) AA or (proton–proton) pp, (proton–nucleus) pA collisions. The production of particles such as pions, kaons and protons has been measured in pp and Pb–Pb collisions at high pT , for Au+Au col- lision,and p +Pb. The transverse momentum distribution of the produced particles in AA collisions has been studied with Boltzmann–Gibbs distribution which takes the exponential form. Boltzmann-Gibbs statistics is a reasonable approximation for studying systems with independent or weakly correlated elements. However, it fails to explain strongly correlated systems with significant long-range correlations and interactions. Tsallis distribution succeeded to explain this kind of systems so, Tsallis distribution fits the transverse momentum distributions observed at the Rel- ativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) very well. It is found that the transverse momentum distribution is a function of the rapidity y, transverse mass mT and transverse momentum pT . The center of mass energy
√SNN is an invariant quantity measured in the center of mass reference frame of
the colliding particles which is defined as the energy needed to create new particles.
In this work, the transverse momentum spectra of some mesons such as pions (π±
and kaons k±) and some baryons such as ( protons p,and anti-protons p) produced in Au–Au collisions at √SNN = 7.7, 11.5, 19.6, 27, 39 GeV , and Λ at 62.4 GeV have
been studied based on Tsallis statistics with fixed Tsallis parameter q which chosen to be in the range 1.09 for all particles under estimation. For pions and Λ, a good fitting is noticed with the experimental data where pions have better fitting than kaons, protons and anti-protons respectively. The volume also for each particle at each energy is extracted by using χ2-fit, but it slightly changed for group of particles such as pions, kaons, and proton, antiproton. Tsallis distribution gives satisfied suc- cessful description of the PT spectra for AA collision at Beam Energy Scan (BES) at wide range of PT but at low PT a deviation appears clearly. For more investigation of Tsallis distribution, the particle ratio is explained well at only small energy but it deviates at large energy.
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The relation between the temperature and some thermodynamics quantities like entropy S, pressure P and energy density ϵ are studied and compared with the available lattice results. The comparison showed that, when the nonextensivity degree (q) increasing, the thermodynamics overestimate the lattice results i.e when q tends to one recovers the Boltzmann distribution agreement with the lattice.