几GeV能量下中心Au+Au碰撞中带电π介子HBT半径劈裂的动力学库仑效应
Dynamical Coulomb effects on charged-pion HBT-radius splitting in central Au+Au collisions at few-GeV energies
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中文总结 AI 辅助
本研究利用UrQMD模型和CRAB程序，通过三种输运情景及残余源处理，探究库仑动力学对Au+Au碰撞中π介子HBT半径劈裂的贡献，发现重子-介子相互作用为主要来源，但不足以完全解释实验数据。
中文摘要 AI 辅助
HADES和STAR合作组观测到了π+π+与π-π- femtoscopic关联随对横动量(k_T)和碰撞能量(√s_NN)的差异。我们研究了在√s_NN=2.42-5.2 GeV的0-10%中心Au+Au碰撞中，这种观测到的劈裂有多少可归因于库仑动力学。使用UrQMD模型和CRAB程序，考虑了依次包含重子-重子、重子-介子和介子-介子库仑相互作用的三种输运情景。在基于重子-重子参考的单独计算中，我们重构了残余带电源的时间依赖有效电荷Z_eff(t)和半径R_eff(t)，并将每个π介子从其各自的最后一次强相互作用点通过演化场传播。计算重现了半径的主要k_T和√s_NN依赖性。在微观计算中，重子-介子库仑相互作用产生了大部分额外的电荷劈裂。残余源处理还相对于参考增强了纵向和侧向半径比，而外向比变化不大，且增强通常随√s_NN增加而减小。在当前框架内，这种贡献不能完全解释数据，促使进一步研究带电源几何及其与强相互作用动力学的相互作用。
英文摘要
The pair transverse momentum ($k_T$) and collision-energy ($\sqrt{s_{NN}}$) dependent difference between $π^{+}π^{+}$ and $π^{-}π^{-}$ femtoscopic correlations was observed by the HADES and STAR Collaborations. We investigate how much of the observed splitting can be accounted for by Coulomb dynamics in 0-10\% central Au+Au collisions at $\sqrt{s_{NN}}=2.42$-5.2 GeV. Using the UrQMD model and the CRAB programme, three transport scenarios that successively include baryon-baryon, baryon-meson, and meson-meson Coulomb interactions are considered. In a separate calculation based on the baryon-baryon reference, we reconstruct the time-dependent effective charge $Z_{\rm{eff}}(t)$ and radius $R_{\rm{eff}}(t)$ of the residual charged source and propagate each pion from its individual last strong-interaction point through the evolving field. The calculations reproduce the main $k_{T}$ and $\sqrt{s_{NN}}$ dependences of the radii. Baryon--meson Coulomb interactions generate most of the additional charge splitting in the microscopic calculation. The residual-source treatment also enhances the longitudinal and sideward radius ratios relative to the reference, whereas the outward ratio changes little, and the enhancement generally decreases with increasing $\sqrt{s_{NN}}$. Within the present framework, this contribution does not fully account for the data, motivating further investigation of the charged-source geometry and its interplay with strong-interaction dynamics.
发表机构
- School of Science, Huzhou Normal University（湖州师范学院理学院）
- Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research（联合核研究所玻戈留博夫理论物理实验室）
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