Glauber模型广泛应用于研究中高能区电荷改变反应截面（CCCS）。该模型以直接质子移除过程为核心图像，为从实验数据出发提取电荷半径提供了理论基础。然而，研究表明，Glauber模型的理论计算值系统性地低于实验测量值。近期研究表明，带电粒子蒸发（CPE）过程，即入射核在经历中子移除后，进一步通过发射带电粒子（如质子、α粒子）使其质子数减小而退激的过程，是解决上述“系统性低估”问题的关键。另一方面，在重靶情况下，一般认为电磁解离（EMD）可能会有比较显著的贡献。在~1 GeV/nucleon以下的能区， EMD贡献是否比较显著的效应仍没有确切的结论。

       为解决上述问题，我们在兰州重离子加速器国家实验室（HIRFL）的RIBLL2束流线上，测量了~370 MeV/nucleon的 ¹⁸O 在碳（C）和铅（Pb）靶上的CCCS，实验截面的不确定度小于4%。通过对反应机制的分解，我们定量评估了直接质子移除、中子移除后的CPE以及EMD三种机制对CCCS的贡献。研究发现，CPE过程对 ¹⁸O 在C和Pb靶上的CCCS贡献分别为12.3%和5.0%，而EMD对CCCS的贡献发现则小于1%。

     为了系统探究EMD的贡献，我们计算了 300与900 MeV/nucleon ¹⁸O 到 ¹⁹⁷Au 等弹核在C、银 (Ag)和Pb等靶上的电荷改变截面，发现EMD随弹核质量数与入射能量的增加呈现显著增强的趋势。例如，对于900 MeV/nucleon ¹⁹⁷Au 在 Pb靶上的CCCS，EMD贡献可达10.5%；然而，对于C靶，所有炮弹的EMD贡献均可忽略。        本工作明确指出，对于300到900 MeV/nucleon的CCCS，需要在直接质子移除的基础上，考虑CPE过程的贡献。同时，对于重弹靶体系，EMD的贡献不可忽略。该研究为中高能重离子反应机制的研究提供了重要参考。研究成果发表于 Physical Review C 112, 014611 (2025)。

     Glauber-type models have been widely used to calculate charge-changing cross sections (CCCSs) at intermediate and high energies. In the models, the direct proton removal provides a theoretical basis for extracting charge radii from experimental data. However, systematic comparisons show that the calculated values are consistently lower than the experimental measurements.  

    Recent studies indicate that charged-particle evaporation (CPE) is a key mechanism to resolve this underestimation. In this process, the projectile first loses one or more neutrons during the collision and then emits charged particles such as protons or α particles to form the final fragment, which reduces its proton number. For heavy targets, electromagnetic dissociation (EMD) can also contribute. Yet, at energies below about 1 GeV/nucleon, quantitative studies of the EMD effect remain limited.

    To address these issues, we measured the CCCSs of ¹⁸O on carbon (C) and lead (Pb) targets at around 370 MeV/nucleon. The experiment was performed at the second Radioactive Ion Beam Line (RIBLL2) of the Heavy Ion Research Facility in Lanzhou (HIRFL). The measurement achieved an uncertainty of less than 4%. By separating the reaction mechanisms, we evaluated the contributions of direct proton removal, CPE after neutron removal, and EMD. The CPE process contributes 12.3% to the CCCS of ¹⁸O on C and 5% on Pb, while the EMD contribution is below 1% at this energy.

    To further explore the EMD effect, we extended the study to projectile–target systems from ¹⁸O to ¹⁹⁷Au on C, sliver (Ag), and Pb at 300 and 900 MeV/nucleon. The EMD contribution on heavy targets (Ag and Pb) increases with both projectile mass and incident energy. For example, it reaches 10.5% for ¹⁹⁷Au on Pb at 900 MeV/nucleon. In contrast, the EMD contribution for all projectiles on C remains negligible.

    This work shows that CCCS in the 300 to 900 MeV/nucleon region need to include the CPE process in addition to direct proton removal. For heavy projectile–target systems, the EMD contribution is also essential. These results provide new insight on the reaction mechanisms of intermediate and high energy heavy-ion collisions. The study has been published in Physical Review C 112, 014611 (2025), DOI: 10.1103/pz8s-j3mc.