Mass spectra and wave functions of TQQQ¯Q¯ tetraquarks
Mass spectra and wave functions of TQQQ¯Q¯ tetraquarks
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DOI：
10.1103/physrevd.104.014018
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发表时间：
2021-04
影响因子：
5
通讯作者：
Qiang Li;Chao-Hsi Chang;Guo-Li Wang;Tianhong Wang
中科院分区：
文献类型：
--
作者：
Qiang Li;Chao-Hsi Chang;Guo-Li Wang;Tianhong Wang
在Bethe-Salpeter框架下研究了具有全重夸克含量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，并进行了数值求解，得到了J^{PC}=0^{++}$，$1^{+-}$，$2^{++}$的四夸克态的相应的质量谱和波函数.计算结果表明，$cc\bar c\bar c$的三个基态位于6.4\sim6.5$GeV的质量范围内，$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态衰变的精确计算。基于所得到的结果，LHCb的观测$X（6900）$不太可能是紧凑的$cc\bar c\bar c$四夸克的基态，但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。
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.