Finding a clean process $B^{-}\to K^{-}{D}^0{K}^0$ to probe absolutely exotic four-quark states

Motivated by the observations of $T_{c\bar{s}0}(2900{)}^0$ and $T_{c\bar{s}0}(2900{)}^{++}$, we propose to search for ${\text{tcsbar}}^0$ in the cleaner process $B^{-}\to K^{-}{D}^0{K}^0$. In the $D^{\ast }{K}^{\ast }$ molecular picture, our estimates suggest that $T_{c\bar{s}0}(2900{)}^0$ should contribute significantly to the $D^0{K}^0$ invariant mass distribution in $B^{-}\to K^{-}{D}^0{K}^0$, as reported by the Belle II Collaboration. The corresponding fit fraction is estimated to be $(9.72\pm 3.92)\mathrm{\%}$ or $(7.09\pm 5.88)\mathrm{\%}$ in different fitting schemes. Further precise measurements of this process at Belle II and LHCb could be helpful for clarifying the nature of $T_{c\bar{s}0}(2900)$.