Exotic ${\bar{D}}_s^{(\ast )}{D}^{(\ast )}$ molecular states and $sc\bar{q}\bar{c}$ tetraquark states with $J^P=0^{+},1^{+},2^{+}$

Abstract

We have calculated the mass spectra for the ${\bar{D}}_s^{(\ast )}{D}^{(\ast )}$ molecular states and $sc\bar{q}\bar{c}$ tetraquark states with $J^P=0^{+},1^{+},2^{+}$. The masses of the axial-vector ${\bar{D}}_s{D}^{\ast }$, ${\bar{D}}_s^{\ast }D$ molecular states and $1_{[sc]}\oplus 0_{[\bar{q}\bar{c}]}$, $0_{[sc]}\oplus 1_{[\bar{q}\bar{c}]}$ tetraquark states are predicted to be around 3.98 GeV, which are in good agreement with the mass of $Z_{cs}(3985{)}^{-}$ from BESIII \cite{besiii2020Zcs}. In both the molecular and diquark-antidiquark pictures, our results suggest that there may exist two almost degenerate states, as the strange partners of the $X(3872)$ and $Z_c(3900)$. We propose to carefully examine the $Z_{cs}(3985)$ in future experiments to verify this. One may also search for more hidden-charm four-quark states with strangeness not only in the open-charm ${\bar{D}}_s^{(\ast )}{D}^{(\ast )}$ channels, but also in the hidden-charm channels ${\eta }_{c}K/K^{\ast }$, $J/\psi K/K^{\ast }$.

Comments: 19 pages, 3 figures. Accepted by Chinese Physics C