Analysis of the tetraquark and hexaquark molecular states with the QCD sum rules

Zhi-Gang Wang

Figure 10. The masses of the tetraquark and hexaquark molecular states with variations of the energy scales $\mu$ of the QCD spectral densities, where the (I), (II) and (III) correspond to the ${D}^{* }{\bar{D}}^{* }$, ${D}^{* }{D}^{* }$ and ${D}^{* }{D}^{* }{\bar{D}}^{* }$ tetraquark and hexaquark molecular states, respectively, the ESF denotes the formulas $M=\sqrt{{\mu }^{2}+4\times {(1.84\mathrm{GeV})}^{2}}$ and $\sqrt{{\mu }^{2}+9\times {(1.84\mathrm{GeV})}^{2}}$, respectively.