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

Abstract

Inspired by a large decay branching ratio (BR) of $B^{+}\to f_{0}(980)K^{+}$ 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 $f_{0}(980)$ could be demonstrated in exclusive $b\to c$ decays by the observation of $f_{0}(980)$ in the final states $\bar{B}\to D^{0(*)} π^{+} π^{-}(KK)$ and $\bar{B}\to J/Ψπ^{+} π^{-}(KK)$. We predict the BRs of $\bar{B}\to D^{0(*)} (J/Ψ) f_{0}(980)$ to be ${\cal {O}}(10^{-4})$ (${\cal {O}}(10^{-5})$) while the unknown wave functions of $D^{(*)0}$ ($J/Ψ$) are chosen to fit the observed decays of $\bar{B}\to D^{(*)0} π^{0} (J/ΨK^{0(*)})$.