Evidence for two-quark content of $f_{0}(980)$ in exclusive $b\to c$ decays

Inspired by large branching ratio (BR) of $B^{+}\to f_{0}(980)K^{+}$ decay measured by Belle recently, we propose that a significant evidence of the component of $n\bar{n}=(u\bar{u}+d\bar{d})/\sqrt{2}$ in $f_{0}(980)$ during its production could be demonstrated by exclusive $b\to c$ processes, in which %$f_{0}(980)$ is reconstructed the reconstructed $f_{0}(980)$ by the decays $\bar{B}\to D^{0(*)} \pi^{+} \pi^{-}(KK)$ and $\bar{B}\to J/\Psi \pi^{+} \pi^{-}(KK)$ is suggested. We predict the BRs of $\bar{B}\to D^{0(*)} (J/\Psi) f_{0}(980)$ to be ${\cal {O}}(10^{-4})$ (${\cal {O}}(10^{-5})$) while the unknown wave functions of $D^{(*)0}$ ($J/\Psi$) are chosen to fit the observed decays $\bar{B}\to D^{(*)0} \pi^{0} (J/\Psi K^{0(*)})$.