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arXiv 2102.05349hep-phhep-exnucl-exnucl-th
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在$D_s^{+}\to π^{+}π^0 η$衰变中能检验$a_0(980)$的性质吗？

Can the nature of $a_0(980)$ be tested in the $D_s^{+}\to π^{+}π^0 η$ decay?

Xi-Zhe Ling, Ming-Zhu Liu, Jun-Xu Lu, Li-Sheng Geng, Ju-Jun Xie

备注：
14 pages, 8 figures
发表信息：
Phys. Rev. D 103, 116016 (2021)
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摘要：

通过对$D^+_s \to π^+ π^0 η$衰变的振幅分析，BESIII合作组首次观测到了$D^+_s \to a_0(980)^+π^0$和$D^+_s \to a_0(980)^0π^+$衰变模式，这两种模式预计将通过纯$W$ -湮灭过程发生。然而，测得的分支分数$\mathcal{B}[D_{s}^{+}\to a_{0}(980)^{+(0)}π^{0(+)},a_{0}(980)^{+(0)}\to π^{+(0)}η]$，发现是大于那些已知的$W$湮灭衰变的一个数量级。如果这两种衰变是由$W$内转换或外发射机制而不是$W$湮灭机制引起的，那么这一矛盾就可以得到调和。在这项工作中，我们提出，$D^+_s$衰减过程通过外部和内部$W$发射，而不是$W$湮灭机制。在这样的情况下，我们执行的$D^+_s \to π^+π^0η$衰变的研究，考虑到从树图$D^+_s \to ρ^+ η\to π^+ π^0 η$和中间$ρ^+ η$和$K^*\bar{K}/K\bar{K}^*$三角图的贡献。$a_0(980)$的中间态可以从耦合的$K \bar{K}$和$πη$通道的终态相互作用中动态产生，并且表明实验数据可以被相当好地描述，这支持将$a_0(980)$解释为分子态。

英文摘要：

From the amplitude analysis of the $D^+_s \to π^+ π^0 η$ decay, the BESIII Collaboration firstly observed the $D^+_s \to a_0(980)^+π^0$ and $D^+_s \to a_0(980)^0π^+$ decay modes, which are expected to occur through the pure $W$-annihilation processes. The measured branching fraction $\mathcal{B}[D_{s}^{+}\to a_{0}(980)^{+(0)}π^{0(+)},a_{0}(980)^{+(0)}\to π^{+(0)}η]$ is, however, found to be larger than those of known $W$-annihilation decays by one order of magnitude. This apparent contradiction can be reconciled if the two decays are induced by internal $W$-conversion or external $W$-emission mechanisms instead of $W$-annihilation mechanism. In this work, we propose that the $D^+_s$ decay proceeds via both the external and internal $W$-emission instead of $W$-annihilation mechanisms. In such a scenario, we perform a study of the $D^+_s \to π^+π^0η$ decay by taking into account the contributions from the tree diagram $D^+_s \to ρ^+ η\to π^+ π^0 η$ and the intermediate $ρ^+ η$ and $K^*\bar{K}/K\bar{K}^*$ triangle diagrams. The intermediate $a_0(980)$ state can be dynamically generated from the final state interactions of coupled $K \bar{K}$ and $πη$ channels, and it is shown that the experimental data can be described fairly well, which supports the interpretation of $a_0(980)$ as a molecular state.

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。

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