AI 中文总结
研究级联半轻子衰变$\Lambda_c^+\to\Lambda^*_{1405/1520}(\to\Sigma\pi)\ell^+\nu_\ell$，用螺旋度振幅形式推导角分布，给出相关数值预测，讨论提取形状因子策略及角可观测量敏感性，还研究了强相位差，为实验分析提供理论指导。
AI 中文摘要
我们使用螺旋度振幅形式研究级联半轻子衰变$\Lambda_c^+\to\Lambda^*_{1405/1520}(\to\Sigma\pi)\ell^+\nu_\ell$，推导完整的四体角分布。明确获得了自旋-1/2和自旋-3/2中间共振的贡献、它们的干涉效应及相应角系数。利用可用的形状因子输入，给出了不变质量分布、螺旋角分布和角不对称性的数值预测。基于这些可观测量，讨论了提取相关形状因子的策略并分析了角可观测量对形状因子变化的敏感性。最后，研究了$\Lambda_c^+\to\Lambda^*$形状因子中的强相位并讨论如何从角分布中提取强相位差。我们的结果为未来实验分析提供了有用的理论指导。
英文摘要
We study the cascade semileptonic decay $Λ_c^+\toΛ^*_{1405/1520}(\toΣπ)\ell^+ν_\ell$ using the helicity amplitude formalism, and derive the full four-body angular distribution. The contributions from the spin-$1/2$ and spin-$3/2$ intermediate resonances, their interference effects, and the corresponding angular coefficients are obtained explicitly. Using available form-factor inputs, we provide numerical predictions for the invariant-mass distribution, helicity-angle distributions, and angular asymmetries. Based on these observables, we discuss strategies for extracting the relevant form factors and analyze the sensitivity of the angular observables to variations in the form factors. Finally, we investigate the strong phases in the $Λ_c^+\toΛ^*$ form factors and discuss how the strong-phase difference can be extracted from the angular distribution. Our results offer useful theoretical guidance for future experimental analyses.
Comments32 pages, 7 figures
