Proton-Number Fluctuations in ²³⁸U+²³⁸U Collisions at √(s_NN) = 2.1 GeV with the CEE Fast Simulation

@misc{lv2026protonnumber,
  title = {{Proton-Number Fluctuations in $^238$U+$^238$U Collisions at $\sqrts_\mathrmNN = 2.1$ GeV with the CEE Fast Simulation}},
  author = {Shuaike Lv and Fan Si and Xionghong He and Xu Sun and Yige Huang and Wanbing He and Yifei Zhang and Ming Shao and Ziyang Li},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.23460},
  eprint = {2610.23460},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.23460},
}

TY  - UNPB
TI  - Proton-Number Fluctuations in ^238U+^238U Collisions at √(s_NN) = 2.1 GeV with the CEE Fast Simulation
AU  - Shuaike Lv
AU  - Fan Si
AU  - Xionghong He
AU  - Xu Sun
AU  - Yige Huang
AU  - Wanbing He
AU  - Yifei Zhang
AU  - Ming Shao
AU  - Ziyang Li
PY  - 2026
DA  - 2026/10/16
PB  - arXiv
DO  - 10.48550/arxiv.2610.23460
UR  - https://arxiv.org/abs/2610.23460
AB  - The Cooling Storage Ring External-target Experiment (CEE) at the Heavy Ion Research Facility in Lanzhou (HIRFL) offers a unique opportunity to map the QCD phase diagram in the high-baryon-density region. In particular, higher-order cumulants (C_r) of event-by-event proton number distributions have been proposed as sensitive probes of the nuclear-matter phase structure. In this work, ^238U+^238U collisions at √(s_NN) = 2.1 GeV are generated using the JAM2 model and then processed through the CEE fast simulation with detector responses. Experimental analysis procedures, including centrality determination and particle identification, are also implemented. Proton-number cumulants up to fourth order and their ratios are calculated and compared with the true values. A track-by-track efficiency correction method is tested by introducing reconstruction efficiency within the TPC acceptance. An additional factor is also included to account for acceptance losses caused by the azimuthal gap between the two TPCs. Within the uncertainties of the current data sample, the corrected cumulants and cumulant ratios are consistent with their generator-level values. The event-sample dependence of the cumulant-ratio uncertainties is further investigated to estimate the statistics required for future measurements, revealing a substantial statistical cost associated with the acceptance compensation. These results provide a simulation-based assessment of the analysis feasibility and statistical requirements for proton-number fluctuation measurements at CEE.
ER  -