同位标量S波D反D分子的辐射衰变
Radiative decays of the isoscalar $S$-wave $D\bar D$ molecule
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中文总结 AI 辅助
该研究假设X₀为纯D反D分子，在有效拉格朗日框架下计算其辐射衰变，得到稳定的衰变比，为X₀的分子结构提供模型无关的信号。
中文摘要 AI 辅助
在强子分子图像中，同位标量S波D反D分子作为X(3872)的自旋0伙伴自然存在。假设该态记为X₀，是具有量子数J^PC=0^{++}的纯D反D分子，我们在有效拉格朗日框架内研究其辐射衰变X₀→γV（V=ρ⁰、ω）。衰变振幅由中间粲介子圈产生，计算过程中始终保持电磁规范不变性。我们计算了分宽度并考察其对X₀质量和截断的依赖关系。尽管单个衰变宽度对截断有显著依赖，但它们的比值却异常稳定，其中X₀→γρ⁰与X₀→γω的衰变比约为2.26，对截断变化不敏感，这一稳健比值为X₀的分子结构提供了有用的不依赖模型的信号。
英文摘要
In the hadronic molecular picture, an isoscalar $S$-wave $D\bar{D}$ molecule is naturally expected as the spin-0 partner of $X(3872)$. Assuming this state, denoted by $X_0$, to be a pure $D\bar D$ molecule with quantum numbers $J^{PC}=0^{++}$, we investigate its radiative decays $X_0\toγV (V=ρ^0,ω)$ within an effective Lagrangian framework. The decay amplitudes are generated by intermediate charmed-meson loops, with electromagnetic gauge invariance consistently maintained throughout the calculation. We evaluate the partial decay widths and examine their dependence on the $X_0$ mass and the cutoff. Although the individual decay widths exhibit a sizable dependence on the cutoff, their ratio is remarkably stable. In particular, we obtain that the ratio for the decays $X_0\toγρ^0$ and $X_0\toγω$ is approximately 2.26, which is insensitive to the variation of the cutoff. This robust ratio provides a useful model-insensitive signature of the molecular structure of $X_0$.
