arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2302.13017hep-phhep-exnucl-exnucl-th
收藏

$X(3872)$的自旋-2伙伴的辐射衰变

Radiative decays of the spin-$2$ partner of $X(3872)$

Pan-Pan Shi, Jorgivan M. Dias, Feng-Kun Guo

备注：
21 pages, 3 figures. Version to appear in PLB
发表信息：
Phys.Lett.B 843 (2023) 137987
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

AI总结：

针对Belle发现的疑似$X(3872)$自旋-2伙伴$X_2$，本文在$D^*\bar D^*$分子图像下计算其辐射衰变宽度与双光子产生事例数，并预言衰变比值小于1.0。

摘要：

人们普遍预期$X(3872)$存在一个自旋为2的伙伴$X_2$，其量子数为$J^{PC}=2^{++}$。在强子分子模型中，它的质量被预言低于$D^*\bar D^*$阈值；Belle合作组在$γψ(2S)$不变质量分布中报道的新结构质量为$M=(4014.3\pm4.0\pm1.5)$ MeV、衰变宽度为$Γ=(4\pm11\pm6)$ MeV，全局显著性为2.8$σ$，是其良好候选者。我们将$X_2$视为$D^*\bar{D}^*$浅束缚态，考虑$X_{2}\to γψ$（其中$ψ=J/ψ、ψ(2S)$）的辐射衰变宽度，并估计在Belle通过双光子碰撞、在$γJ/ψ\toγ\ell^+\ell^-$（$\ell=e,μ$）末态中可收集的$X_2$事例数。基于BESIII测量的$X(3872)\to γψ(2S)$与$X(3872)\to γJ/ψ$衰变宽度比值上限，我们预言类似比值$Γ(X_2\to γψ(2S))/Γ(X_2\to γJ/ψ)$小于1.0。我们建议通过双光子融合在$γJ/ψ$不变质量分布中寻找$X_2$信号。这些结果将有助于深入理解$X(3872)$以及Belle观测到的新结构。

英文摘要：

It has been generally expected that the $X(3872)$ has a spin-2 partner, $X_2$, with quantum numbers $J^{PC}=2^{++}$. In the hadronic molecular model, its mass was predicted to be below the $D^*\bar D^*$ threshold, and the new structure reported in the $γψ(2S)$ invariant mass distribution by the Belle Collaboration with mass $M= (4014.3 \pm 4.0 \pm 1.5)$ MeV and decay width $Γ= (4 \pm 11 \pm 6)$ MeV, with a global significance of 2.8 $σ$, is a nice candidate for it. We consider the radiative decay widths for the $X_{2}\to γψ$ with $ψ=J/ψ, ψ(2S)$ treating the $X_2$ as a $D^*\bar{D}^*$ shallow bound state, and estimate the events of $X_2$ in two-photon collisions that can be collected in the $γJ/ψ\toγ\ell^+\ell^-$ ($\ell=e,μ$) final states at Belle. Based on the upper limit for the ratio of decay widths of $X(3872)\to γψ(2S)$ and $X(3872)\to γJ/ψ$ measured by BESIII, we predict the similar ratio $Γ(X_2\to γψ(2S))/Γ(X_2\to γJ/ψ)$ to be smaller than $1.0$. We suggest searching for the $X_2$ signal in the $γJ/ψ$ invariant mass distribution via two-photon fusions. The results will lead to insights into both the $X(3872)$ and the new structure observed by Belle.

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。

↑