Final state interaction effects in $B^+\to D^+K^0$ decay

In this research the exclusive decay of $B^+\to D^+K^0$ is calculated by QCD factorization method (QCDF) and final state interaction (FSI). First, the $B^+\to D^+K^0$ decay is calculated via QCDF method. The result that is found by using the QCDF method is less than the experimental result. So FSI is considered to solve the $B^+\to D^+K^0$ decay. For this decay, the $D_s^+\pi^0$, ${D_s^+}^*\rho^0$, ${D_s^+}^*\phi$ via the exchange of $\bar{K}^0$, ${\bar{K}^0 }^*$, $D^-$, and ${D^- }^*$ mesons are chosen for the intermediate states. The above intermediate states are calculated by using the QCDF method. In the FSI effects, the results of our calculations depend on $\eta$ as the phenomenological parameter. The range of this parameter is selected from $2$ to $2.4$. It is found that if $\eta=2.4$ is selected, the numbers of the branching ratio are placed in the experimental range. The experimental branching ratio of this decay is less than $2.9\cdot10^{-6}$ and our results calculated by QCDF and FSI are $(0.16\pm0.04)\cdot10^{-6}$ and $(2.8\pm0.09)\cdot10^{-6}$ respectively.