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arXiv 2103.13140hep-phhep-ex
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四夸克态$X(6900)$和双夸克与反双夸克的相互作用

Tetraquark state $X(6900)$ and the interaction between diquark and antidiquark

Hong-Wei Ke, Xin Han, Xiao-Hai Liu, Yan-Liang Shi

摘要:

最近LHCb在终态di- $J/ψ$中宣布了一种新的结构$X(6900)$,它通常被认为是$cc$ - $\bar c\bar c$四夸克态. %大众。在Bethe-Salpeter(B-S)框架下研究了可能的$cc$ - $\bar c\bar c$束缚态以及双夸克态($cc$)和反双夸克态($\bar c\bar c$)之间的相互作用.本文将$cc$($\bar c\bar c$)视为一个反三重态(三重态)轴矢量,得到$cc$ - $\bar c\bar c$结合态的量子数分别为$0^+$,$1^+$和$2^+$ .从介子的相互作用出发,利用有效耦合,提出了双夸克和反双夸克系统的相互作用核。然后推导了不同量子数下的B-S方程。通过数值求解这些方程,我们发现当适当地选取相互作用(核)中引入的参数$κ$时,某些激发态的光谱可以接近于$X(6900)$的质量,我们还简要地计算了$bb$ - $\bar b\bar b$束缚态的光谱.未来对$bb$ - $\bar b\bar b$状态的测量将有助于我们确定有效相互作用的确切形式。

英文摘要:

Recently LHCb declared a new structure $X(6900)$ in the final state di-$J/ψ$ which is popularly regarded as a $cc$-$\bar c\bar c$ tetraquark state. %popularly. Within the Bethe-Salpeter (B-S) frame we study the possible $cc$-$\bar c\bar c$ bound states and the interaction between diquark ($cc$) and antidiquark ($\bar c\bar c$). In this work $cc$ ($\bar c\bar c$) is treated as a color anti-triplet (triplet) axial-vector so the quantum numbers of $cc$-$\bar c\bar c$ bound state are $0^+$, $1^+$ and $2^+$. Learning from the interaction in meson case and using the effective coupling we suggest the interaction kernel for diquark and antidiquark system. Then we deduce the B-S equations for different quantum numbers. Solving these equations numerically we find the spectra of some excited states can be close to the mass of $X(6900)$ when we assign appropriate values for parameter $κ$ introduced in the interaction (kernel).We also briefly calculate the spectra of $bb$-$\bar b\bar b$ bound states. Future measurement of $bb$-$\bar b\bar b$ state will help us to determine the exact form of effective interaction.

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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