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 $\bar{B}\to D^{0(\ast )}{\pi }^{+}{\pi }^{-}(KK)$ and $\bar{B}\to J/\Psi {\pi }^{+}{\pi }^{-}(KK)$. We predict the BRs of $\bar{B}\to D^{0(\ast )}(J/\Psi )f_0(980)$ to be $\mathcal{O}(10^{-4})$ ($\mathcal{O}(10^{-5})$) while the unknown wave functions of $D^{(\ast )0}$ ($J/\Psi$) are chosen to fit the observed decays of $\bar{B}\to D^{(\ast )0}{\pi }^0(J/\Psi K^{0(\ast )})$.

4 pages, 2 figures, Revtex4, version to appear in PRD