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Bibliographic Details
Main Authors: Si, Dawei, Xiao, Sheng, Qin, Zhi, Qin, Yuhao, Xu, Junhuai, Tian, Baiting, Zhang, Boyuan, Zhang, Haojie, Guo, Dong, Wang, Yijie, Wei, Xiaobao, Hao, Yibo, Wang, Zengxiang, Zhuo, Tianren, Ma, Chunwang, Yang, Yuansheng, Wei, Xianglun, Yang, Herun, Ma, Peng, Duan, Limin, Duan, Fangfang, Wang, Kang, Ma, Junbing, Xu, Shiwei, Bai, Zhen, Yang, Guo, Yang, Yanyun, Xiao, Zhigang
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2501.09576
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Table of Contents:
  • The neutron-neutron ($nn$) correlation function has been measured in 25 MeV/u $^{124}$Sn+$^{124}$Sn reactions. Using the Lednický-Lyuboshitz approach, the $nn$ scattering length and effective range ($f_{0}^{nn}$, $d_{0}^{nn}$), as well as the reduced space-time size $R^{(0)}$ of the neutron emission source are simultaneously extracted as ($18.9^{+1.3}_{-1.2}$ fm, $1.9^{+1.3}_{-1.0}$ fm) and $4.12 \pm 0.12$ fm, respectively. The measured $nn$ scattering length is consistent with the results obtained in the low-energy scattering $^{2}{\rm H}(π^{-},γ)2n$, indicating heavy-ion collisions can serve as an effective approach for measuring $nn$ interactions and further investigating the charge symmetry breaking of nuclear force. The space-time size extracted from momentum-gated correlation functions exhibits clear dependence on the pair momentum, with $R^{(0)}=2.8 \pm 0.1 $ fm and $4.9 \pm 0.2$ fm being determined for the high and low momentum neutrons, respectively.