$B\to f_0(980)K^{(\ast )}$ decays and final state interactions

We study the exclusive decays of $B\to f_0(980)K^{(\ast )}$ in the framework of the perturbative QCD by identifying the $f_0(980)$ as the composition of $\bar{s}s$ and $\bar{n}n=(\bar{u}u+\bar{d}d)\mathrm{/}\sqrt{2}$. We find that the influence of the $\bar{n}n$ content on the predicted branching ratios is crucial. We discuss the possible rescattering and gluonium states which could enhance the branching ratios of considered decays. We point out that the CP asymmetry in $B\to f_0(980)K_{S,L}$ could be a new explorer of $\sin 2{\varphi }_1$.