AI 中文总结
本文针对相对论平均场模型中自由核子流的离壳歧义问题，采用自由核子产生湮灭算符定义流，消除了狄拉克代数相关歧义，并成功解决了相干π光生过程中的极大歧义。
AI 中文摘要
相对论平均场模型是模拟原子核上半轻子散射和光生过程的有用工具。当使用自由核子流时，常存在所谓的“离壳歧义”。本文证明，当流由自由核子产生和湮灭算符定义时，所有与壳上/离壳狄拉克代数相关的歧义均消失；真正的歧义源于流本身依赖于负责核结合的平均场，若采用与背景场一致的流，这些歧义可被消除。作为应用，本文研究了原子核的弹性散射，以及文献中报道的相干π光生过程中存在的极大歧义，并说明本文提出的方法如何消除这些歧义。
英文摘要
Relativistic mean field models are a useful tool for modeling semi-leptonic scattering and photo production on nuclei. When using free-nucleon currents, it is often claimed that there exist so-called ``off-shell ambiguities''. Here we show that when the current is defined in terms of free-nucleon creation and annihilation operators, all ambiguities related to on-shell vs. off-shell Dirac algebra disappear. Genuine ambiguities persist because the current itself depends on the mean field responsible for nuclear binding; these would be fixed if a consistent background-field dependent current were used. As applications, we consider elastic scattering from a nucleus, and (very large) ambiguities that were previous reported in the literature in the context of coherent pion photoproduction. We explain how these ambiguities are removed by the procedure introduced herein.
