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  • Open Access

Deciphering the universal scaling of particle transverse momentum spectra in heavy-ion collisions

Xi-Yao Guo1, Hua Zheng1,*, Wen-Chao Zhang1, Li-Lin Zhu2, Xing-Quan Liu3, Zhi-Guang Tan4, Dai-Mei Zhou5, and Ben-Hao Sa5,6

  • *Contact author: zhengh@snnu.edu.cn
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Phys. Rev. C 114, 024902 – Published 3 August, 2026

DOI: https://doi.org/10.1103/2dp4-q43h

Abstract

We systematically investigate the scaling properties of the transverse momentum spectra for pions, kaons, and protons in Au+Au collisions at sNN=7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV, as well as in U+U collisions at sNN=193GeV, across different centrality classes, using experimental data from the collaborations at the Relativistic Heavy Ion Collider (RHIC). Universal scaling emerges when the particle transverse momentum spectra are scaled by global physical quantities, i.e., the average total particle multiplicity and mean transverse momentum, confirming recent scaling findings from the data at the Large Hadron Collider (LHC) by the ExTrEMe Collaboration. The scaling behavior breaks down in the high pT region and in peripheral collisions. We provide a natural explanation for these observations in the framework of a blast-wave-type model built upon the Cooper-Frye formula. Furthermore, we demonstrate the equivalence between the scaling found by the ExTrEMe Collaboration and the Hwa-Yang scaling, which was proposed two decades ago.

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Outline

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Phys. Rev. C 114, 024902– Published 3 August, 2026
  • Received 20 April 2026
  • Revised 6 June 2026
  • Accepted 8 July 2026
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