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arXiv 2104.12372hep-ph
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$T_{QQ\bar Q\bar Q}$四夸克态的质量谱和波函数

Mass spectra and wave functions of $T_{QQ\bar Q\bar Q}$ tetraquarks

Qiang Li, Chao-Hsi Chang, Guo-Li Wang, Tianhong Wang

摘要:

在Bethe-Salpeter框架下研究了具有全重夸克含量$QQ\bar Q\bar Q$的紧致四夸克态作为双夸克-反双夸克的束缚态.所用的(反)双夸克质量和形状因子与我们在以前的工作中计算的二重重子相同。在瞬时近似下,导出了四夸克态的三维(Bethe-)Salpeter方程,并数值求解,得到了相应的四夸克态的$J^{PC}=0^{++}$、$1^{+-}$和$2^{++}$的质量谱和波函数.结果表明,$cc\bar c\bar c$的三个基态位于$6.4\sim6.5$ GeV的质量范围内,而$bb\bar b\bar b$的三个基态位于$19.2\sim19.3$ GeV的质量范围内.所得到的相对论性波函数自然地包含了可能的$D$ \(或$G$)分波的混合效应,从而可以进一步用于四夸克衰变的精确计算.根据所得结果,LHCb观测到的$X(6900)$不太可能是致密$cc\bar c\bar c$四夸克态的基态,而可能是第一或第二激发态.此外,一个广泛使用的传播的形状因子也进行了研究和讨论。

英文摘要:

The compact tetraquark states with fully heavy quark contents $QQ\bar Q\bar Q$ are studied as the bound states of the diquark-antidiquark within the Bethe-Salpeter framework. The (anti)diquark masses and form factors used are the same as we calculated the doubly heavy baryons in a previous work. Under the instantaneous approximation, the three-dimensional (Bethe-)Salpeter equation of the tetraquarks is derived and solved numerically to obtain the corresponding mass spectra and wave functions of the tetraquarks with $J^{PC}=0^{++}$, $1^{+-}$, and $2^{++}$. Our results show that the three ground states of $cc\bar c\bar c$ locate in the mass range of $6.4\sim6.5$GeV, and the $bb\bar b\bar b$ states in mass range of $19.2\sim19.3$GeV. The obtained relativistic wave functions naturally include the mixing effects from the possible $D$\,(or $G$) partial waves, and then can be further used to do precise calculations of the tetraquark decays. Based on the obtained results, the LHCb's observation $X(6900)$ is less likely to be the ground states of compact $cc\bar c\bar c$ tetraquarks but might be the first or second excited states. In addition, a widely used propagator-like form factor is also investigated and discussed.

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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