Analysis of Midrapidity pT Distributions of Identified Charged Particles in Pb + Pb Collisions at (Formula presented.) TeV Using Tsallis Distribution with Embedded Transverse Flow
Olimov K.K. Liu F.-H. Fedosimova A.I. Lebedev I.A. Deppman A. Musaev K.A. Shodmonov M.Z. Tukhtaev B.J.
August 2022MDPI
Universe
2022#8Issue 8
The midrapidity transverse momentum distributions of the charged pions, kaons, protons, and antiprotons, measured by ALICE Collaboration at ten centrality classes of Pb + Pb collisions at (Formula presented.) = 5.02 TeV in the Large Hadron Collider (LHC, CERN, Switzerland), are successfully analyzed using combined minimum χ2 fits with a thermodynamically non-consistent, as well as thermodynamically consistent, Tsallis function with transverse flow. The extracted non-extensivity parameter q decreases systematically for all considered particle species with increasing Pb + Pb collision centrality, suggesting an increase in the degree of system thermalization with an increase in collision centrality. The results for q suggest quite a large degree of thermalization of quark–gluon plasma (QGP) created in central Pb + Pb collisions at (Formula presented.) = 5.02 TeV with the average number of participant nucleons (Formula presented.) > 160. The obtained significantly different growth rates of transverse flow velocity, (Formula presented.), in regions (Formula presented.) < 71 ± 7 and (Formula presented.) > 71 ± 7 with the temperature parameter T0 remaining constant within uncertainties in region (Formula presented.) > 71 ± 7 probably indicates that (Formula presented.) ≈ 71 ± 7 (corresponding to (Formula presented.) ≈ 251 ± 20) is a threshold border value for a crossover transition from a dense hadronic state to the QGP phase (or mixed phase of QGP and hadrons) in Pb + Pb collisions at (Formula presented.) = 5.02 TeV. The threshold border value for transverse flow velocity (Formula presented.) ≈ 0.46 ± 0.03 (corresponding to (Formula presented.) ≈ 71 ± 7), estimated by us in Pb + Pb collisions at (Formula presented.) = 5.02 TeV, agrees well with the corresponding border value (Formula presented.) ≈ 0.44 ± 0.02, recently obtained in Xe + Xe collisions at (Formula presented.) = 5.44 TeV, and with almost constant (Formula presented.) values extracted earlier in the Beam Energy Scan (BES) program of the Relativistic Heavy-Ion Collider (RHIC, Brookhaven, GA, USA) in central Au + Au collisions in the (Formula presented.) = 7.7 − 39 GeV energy range, where the threshold for QGP production is achieved. The correlations between extracted T0 and (Formula presented.) parameters are found to be greatly different in regions (Formula presented.) < 0.46 and (Formula presented.) > 0.46, which further supports our result obtained for the threshold border value in Pb + Pb collisions at (Formula presented.) = 5.02 TeV.
deconfinement phase transition , heavy-ion collisions at the LHC , non-extensive Tsallis statistics with included transverse flow , thermalization of collision system , transverse momentum distributions of particles
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Physical-Technical Institute of Uzbekistan Academy of Sciences, Chingiz Aytmatov Str. 2b, Tashkent, 100084, Uzbekistan
National University of Science and Technology MISIS (NUST MISIS), Almalyk Branch, Almalyk, 110105, Uzbekistan
Institute of Theoretical Physics Collaborative Innovation Center of Extreme Optics State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan, 030006, China
Institute of Nuclear Physics, Almaty, 050032, Kazakhstan
Institute of Physics and Technology, Satbayev University, Almaty, 050032, Kazakhstan
Instituto de Física, Universidade de São Paulo, SP, São Paulo, 05580-090, Brazil
Physical-Technical Institute of Uzbekistan Academy of Sciences
National University of Science and Technology MISIS (NUST MISIS)
Institute of Theoretical Physics Collaborative Innovation Center of Extreme Optics State Key Laboratory of Quantum Optics and Quantum Optics Devices
Institute of Nuclear Physics
Institute of Physics and Technology
Instituto de Física
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