On the nature of

A near-threshold enhancement in the $$D^{+}_{s}D^{-}_{s}$$ system, dubbed as X(3960), is observed by the LHCb collaboration recently. A combined analysis on $$\chi _{c0}(3930)~(\rightarrow D^+ D^-)$$, $$X(3960)~(\rightarrow D^{+}_{s}D^{-}_{s})$$, and $$X(3915)~(\rightarrow J/\psi \omega )$$ is performed using both a K-matrix approach of $$D_{(s)}\bar{D}_{(s)}$$ four-point contact interactions and a model of Flatté-like parameterizations. The use of the pole counting rule and spectral density function sum rule indicate, under current statistics, that this $$D^{+}_{s}D^{-}_{s}$$ near-threshold state has probably the mixed nature of a $$c\bar{c}$$ confining state and $$D^{+}_{s}D^{-}_{s}$$ continuum