发表机构
Institute of Experimental Physics I, Ruhr University Bochum, Germany（波鸿鲁尔大学实验物理第一研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文利用 GlueX 数据测量光生 $\rho^-\Delta^{++}$ 的自旋密度矩阵元，首次应用联合自旋密度矩阵的完整形式体系，并验证因子化模型的适用性，为研究混合介子产生机制提供关键实验依据。
AI 中文摘要
位于杰斐逊实验室 Hall D 的 GlueX 实验旨在绘制轻夸克介子的完整谱系，重点研究混合介子，即胶子场被激发并贡献于介子量子数的态。寻找奇异混合介子需要深入理解底层产生机制。极化观测量，如自旋密度矩阵元（SDMEs），是研究这些机制的重要实验工具。本文报道了利用 GlueX 数据测量光生 $\rho^-\Delta^{++}$ 过程中非极化和极化 SDMEs 的结果。在本分析中，首次应用了正确的完整形式体系，其中上层介子系统和下层重子系统由联合自旋密度矩阵描述。一个因子化模型给出的结果与完整模型的结果一致，表明这种简化描述也可能适用于涉及介子-重子末态的其他反应。
英文摘要
The GlueX experiment, located in Hall D at Jefferson Lab, aims to map the full spectrum of light-quark mesons with an emphasis on hybrid mesons, states in which the gluonic field is excited and contributes to the quantum numbers of the meson. The search for exotic hybrid mesons requires a detailed understanding of the underlying production mechanisms. Polarization observables, such as the spin-density matrix elements (SDMEs), are an important experimental tool to investigate these mechanisms. The measurement of the unpolarized and polarized SDMEs in the photoproduction of $ρ^-Δ^{++}$ using GlueX data is reported. In this analysis, for the first time, the correct full formalism is applied in which the upper mesonic and lower baryonic systems are described by a joint spin-density matrix. A factorized model yields results consistent with those of the full model, suggesting that this simplified description may also be suitable for other reactions involving meson-baryon final states.
