Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2018, Vol. 29 ›› Issue (6): 82 doi: 10.1007/s41365-018-0425-x


Kinetic freeze-out temperatures in central and peripheral collisions: Which one is larger?

Hai-Ling Lao, Fu-Hu Liu, Bao-Chun Li, Mai-Ying Duan   

  1. Institute of Theoretical Physics and State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China
  • Contact: Fu-Hu Liu;
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (Nos. 11575103 and 11747319), the Shanxi Provincial Natural Science Foundation (No. 201701D121005), and the Fund for Shanxi ‘‘1331 Project’’ Key Subjects Construction.

Hai-Ling Lao, Fu-Hu Liu, Bao-Chun Li, Mai-Ying Duan. Kinetic freeze-out temperatures in central and peripheral collisions: Which one is larger?.Nuclear Science and Techniques, 2018, 29(6): 82     doi: 10.1007/s41365-018-0425-x


The kinetic freeze-out temperatures, T0, in nucleus–nucleus collisions at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies are extracted by four methods: (1) the Blast-Wave model with Boltzmann–Gibbs statistics (the BGBW model), (2) the Blast-Wave model with Tsallis statistics (the TBW model), (3) the Tsallis distribution with flow effect (the improved Tsallis distribution), and (4) the intercept in T =T0 + am0 (the alternative method), where m0 denotes the rest mass and T denotes the effective temperature which can be obtained by different distribution functions. It is found that the relative sizes of T0 in central and peripheral collisions obtained by the conventional BGBW model which uses a zero or nearly zero transverse flow velocity, βT, are contradictory in tendency with other methods. With a re-examination for βT in the first method, in which βT is taken to be ∽(0.40 ± 0.07) c, a recalculation presents a consistent result with others. Finally, our results show that the kinetic freeze-out temperature in central collisions is larger than that in peripheral collisions.

Key words: Kinetic freeze-out temperature, Methods for extraction, Central collisions, Peripheral collisions