发表机构
Sardar Vallabhbhai National Institute of Technology（萨达尔·瓦拉巴伊国立技术学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究针对窄P_c态的开粲衰变，用夸克交换模型预言其衰变宽度层级，发现π介子交换结果可量化匹配敏感性，Λ_c\bar{D}^*模式测量可检验相关规律。
AI 中文摘要
窄P_c(4312)、P_c(4440)和P_c(4457)结构与Σ_c\bar{D}^{(*)}阈值的接近性，促使人们将其解释为强子分子。我们将P_c(4312)视为具有J^P=1/2^-的S波Σ_c\bar{D}态，并对每个较重的峰分别检验J^P=1/2^-和3/2^-的Σ_c\bar{D}^*归属。在夸克交换模型的玻恩近似下，计算了选定的S波开粲跃迁到Λ_c\bar{D}^{(*)}的过程，包括前后重排图及其色、味、自旋和空间矩阵元。在所考虑的输入参数变化范围内，对于每个J^P=1/2^-的归属，夸克交换宽度均稳健地倾向于Λ_c\bar{D}^*而非Λ_c\bar{D}。在任一较重峰的质量处，J^P=3/2^-对应的Λ_c\bar{D}^*宽度相对于J^P=1/2^-被压低约一个数量级，为自旋归属提供了基于衰变的潜在判别依据。较大的道层级源于自旋无关项与超精细项之间的空间重叠和干涉，并非普适的重夸克自旋对称比值。我们还探讨了一阶玻恩近似下的延迟单π介子交换跃迁，其对P_c(4312)→Λ_c\bar{D}^*的影响最强，而相干宽度仍对截断、能量转移方案、短程减除及未解决的相对匹配符号敏感。因此，夸克交换层级是核心预言，而π介子交换结果则量化了匹配敏感性，对Λ_c\bar{D}^*模式的测量可直接检验这些规律。
英文摘要
The proximity of the narrow $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ structures to the $Σ_c\bar D^{(*)}$ thresholds motivates their interpretation as hadronic molecules. We treat the $P_c(4312)$ as an $S$-wave $Σ_c\bar D$ state with $J^P=1/2^-$ and examine both $J^P=1/2^-$ and $3/2^-$ $Σ_c\bar D^*$ assignments for each heavier peak. The selected $S$-wave open-charm transitions to $Λ_c\bar D^{(*)}$ are calculated at Born order in the quark-interchange model, including the prior and post rearrangement diagrams and their color, flavor, spin, and spatial matrix elements. Across the input variations considered, the quark-interchange widths robustly favor $Λ_c\bar D^*$ over $Λ_c\bar D$ for every $J^P=1/2^-$ assignment. At either heavier peak mass, the $Λ_c\bar D^*$ width for $J^P=3/2^-$ is suppressed by approximately one order of magnitude relative to $J^P=1/2^-$, providing a potential decay-based discriminator of the spin assignments. The large channel hierarchies arise from spatial overlaps and interference between spin-independent and hyperfine contributions and are not universal heavy-quark-spin-symmetry ratios. We also explore a retarded one-pion-exchange transition at first Born order. It affects $P_c(4312)\toΛ_c\bar D^*$ most strongly, while the coherent widths remain sensitive to the cutoff, energy-transfer prescription, short-distance subtraction, and unresolved relative matching sign. The quark-interchange hierarchies are therefore the central predictions, whereas the pion-exchange results quantify matching sensitivity. Measurements of the $Λ_c\bar D^*$ modes can directly test these patterns.
Comments33 pages, 4 figures (Accepted in PRD)
