On leptonic width of X (4260)

New measurements on cross sections in $$e^+e^-\rightarrow J/\psi \pi ^+\pi ^-$$ , $$h_c\pi ^+\pi ^-$$ , $$D^0D^{*-}\pi ^++c.c.$$ , $$\psi (2S)\pi ^+\pi ^-$$ , $$\omega \chi _{c0}$$ and $$J/\psi \eta $$ channels have been carried out by BESIII, Belle and BABAR experiments, as well as in the $$D_s^{*+}D_s^{*-}$$ channel. We perform extensive numerical analyses by combining all these data available, together with those in $$D^+D^{*-}+c.c.$$ and $$D^{*+}D^{*-}$$ channels. Though the latter show no evident peak around $$\sqrt{s}=4.230$$ GeV, the missing X(4260) is explained as that it is concealed by the interference effects of the well established charmonia $$\psi (4040)$$ , $$\psi (4160)$$ and $$\psi (4415)$$ . Our analyses reveal that the leptonic decay width of X(4260) ranges from $$\mathcal {O}(10^2)$$ eV to $$\mathcal {O}(1)$$ keV, and hence it is probably explained in the conventional quark model picture. That is, the X(4260) may well be interpreted as a mixture of $$4^3S_1$$ and $$3^3D_1$$ ( $$2^3D_1$$ ) states.