arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2101.02872hep-phhep-th
收藏

强子分子图象中$Ξ(1620)$的辐射衰变

Radiative decay of the $Ξ(1620)$ in a hadronic molecule picture

HongQiang Zhu, Feng Yang, Yin Huang

摘要:

去年,在粒子数据组(PDG)中编目的只有一颗恒星的$Ξ(1620)$状态再次被Belle合作组织报道为$Ξ^{-}π^{+}$最终状态。它的性质,不仅光谱,而且衰变宽度不能简单地解释的背景下,传统的组分夸克模型。这引起了对这种共振结构的积极讨论。在本工作中,我们假设新观测到的$Ξ(1620)$是一个具有自旋宇称$J^P=1/2^{-}$的$Λ\bar{K}$和$Σ\bar{K}$的介子-重子分子态,研究了它的辐射衰变。利用有效拉格朗日量计算了$Λ\bar{K}-Σ\bar{K}$分子态通过强子环到$Ξγ$和$Ξπγ$末态的部分衰变宽度。$Ξ(1620)^0\toγΞ$和$Ξ(1620)^0\toγΞπ$的部分宽度被评估为分别约为$118.76-174.21$ KeV和$58.19-68.75$ eV,其可被LHC b接近。如果$Ξ(1620)$是$Λ\bar{K}-Σ\bar{K}$分子,则辐射跃迁强度$Ξ(1620)^0\toγ\bar{K}Λ$相当小,并且衰变宽度为0.01 eV的量级。这些过程的未来实验测量可能有助于测试$Ξ(1620)$的分子解释。

英文摘要:

Last year, the $Ξ(1620)$ state that is cataloged in the Particle Data Group (PDG) with only one star is reported again in the $Ξ^{-}π^{+}$ final state by the Belle Collaboration. Its properties not only the spectroscopy but also the decay width cannot be simply explained in the context of conventional constituent quark models. This intrigues an active discussion on the structure of this resonance. In this work, we study the radiative decays of the newly observed $Ξ(1620)$ assuming that it is a meson-baryon molecular state of $Λ\bar{K}$ and $Σ\bar{K}$ with spin-parity $J^P=1/2^{-}$ in our previous work. The partial decay widths of the $Λ\bar{K}-Σ\bar{K}$ molecular state into $Ξγ$ and $Ξπγ$ final states through hadronic loops are evaluated with the help of the effective Lagrangians. The partial widths for the $Ξ(1620)^0\toγΞ$ and $Ξ(1620)^0\toγΞπ$ are evaluated to be about $118.76-174.21$ KeV and $58.19-68.75$ eV, respectively, which may be accessible for the LHCb. If the $Ξ(1620)$ is $Λ\bar{K}-Σ\bar{K}$ molecule, the radiative transition strength $Ξ(1620)^0\toγ\bar{K}Λ$ is quite small and the decay width is of the order of 0.01 eV. Future experimental measurements of these processes can be useful to test the molecule interpretations of the $Ξ(1620)$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑