Analysis of the hadronic molecules $DK$, $D^{\ast }K$, $D{K}^{\ast }$ and their bottom analogs with QCD sum rules

In this work, we construct the color-singlet-color-singlet type currents to study the masses and pole residues of charm-strange tetraquark states and their bottom analogs with $J^P$ = $0^{+}$ and $1^{+}$ by using two-point QCD sum rules, where the vacuum condensates are considered up to dimension 12. The predicted masses for $DK$, $D^{\ast }K$ and $D{K}^{\ast }$ molecular states are $2.322_{-0.072}^{+0.066}$ GeV, $2.457_{-0.068}^{+0.064}$ GeV and $2.538_{-0.062}^{+0.059}$ GeV. These results are consistent well with the experimental data of $D_{s0}(2317)$, $D_{s1}(2460)$ and $D_{s1}(2536)$, respectively. The theoretical results for $BK$ and $B^{\ast }K$ molecular states are $5.970_{-0.064}^{+0.061}$ GeV and $6.050_{-0.064}^{+0.062}$ GeV which are all higher than their own thresholds. Finally, the mass of hadronic molecule $B{K}^{\ast }$ is predicted to be $6.158_{-0.063}^{+0.061}$ GeV. This value is lower than the threshold of $B{K}^{\ast }$, which implies that it may be a bound hadronic molecular state.