Mean-pT fluctuations in Au+Au collisions at √(sNN)=3.0--$19.6$ GeV within JAM2
Abstract
Event-by-event mean-pT fluctuations probe initial-state fluctuations and their evolution through the dynamics of heavy-ion collisions. We study second-order mean-pT fluctuations in Au+Au collisions at √(sNN)=3.0--$19.6$ GeV using JAM2 in the RQMDv mean-field mode with the MH2 parameterization. The model qualitatively reproduces the measured identified-particle pT spectra, providing a single-particle baseline for the fluctuation analysis. The scaled fluctuation k2 decreases with increasing ⟨ Npart⟩ and shows broad agreement with the available measurements at 7.7--19.6 GeV, whereas its calculated centrality dependence is stronger than that in the data at 3.0--4.5 GeV. For the combined proton-plus-antiproton sample, the unnormalized correlator ⟨ c2⟩ is positive and larger than that for charged pions. The charged-pion correlator ⟨ c2⟩ is negative or consistent with zero over most centrality intervals at 3.0 and 3.5 GeV, becomes weakly positive at 4.5 GeV, and remains positive at higher energies. Its energy evolution resembles the change in the reaction-plane elliptic flow, but this comparison does not establish a common microscopic origin. These calculations provide species-dependent predictions within a transport model without an explicit partonic stage. Isolating the contributions of mean fields, rescattering, and spectator interactions requires controlled variations of the transport dynamics.
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BibTeX
@misc{liu2026meanpt,
title = {{Mean-$p_T$ fluctuations in Au+Au collisions at $\sqrts_\rm NN=3.0$--$19.6$ GeV within JAM2}},
author = {Yaqi Liu and Liuyao Zhang and Chunjian Zhang and Jinhui Chen and Chunwang Ma},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.28074},
eprint = {2609.28074},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.28074},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Mean-p_T fluctuations in Au+Au collisions at √(s_NN)=3.0--$19.6$ GeV within JAM2
AU - Yaqi Liu
AU - Liuyao Zhang
AU - Chunjian Zhang
AU - Jinhui Chen
AU - Chunwang Ma
PY - 2026
DA - 2026/09/23
PB - arXiv
DO - 10.48550/arxiv.2609.28074
UR - https://arxiv.org/abs/2609.28074
AB - Event-by-event mean-p_T fluctuations probe initial-state fluctuations and their evolution through the dynamics of heavy-ion collisions. We study second-order mean-p_T fluctuations in Au+Au collisions at √(s_NN)=3.0--$19.6$ GeV using JAM2 in the RQMDv mean-field mode with the MH2 parameterization. The model qualitatively reproduces the measured identified-particle p_T spectra, providing a single-particle baseline for the fluctuation analysis. The scaled fluctuation k_2 decreases with increasing ⟨ N_part⟩ and shows broad agreement with the available measurements at 7.7--19.6 GeV, whereas its calculated centrality dependence is stronger than that in the data at 3.0--4.5 GeV. For the combined proton-plus-antiproton sample, the unnormalized correlator ⟨ c_2⟩ is positive and larger than that for charged pions. The charged-pion correlator ⟨ c_2⟩ is negative or consistent with zero over most centrality intervals at 3.0 and 3.5 GeV, becomes weakly positive at 4.5 GeV, and remains positive at higher energies. Its energy evolution resembles the change in the reaction-plane elliptic flow, but this comparison does not establish a common microscopic origin. These calculations provide species-dependent predictions within a transport model without an explicit partonic stage. Isolating the contributions of mean fields, rescattering, and spectator interactions requires controlled variations of the transport dynamics.
ER -