Will the subprocesses $\rho(770,1450)^0\to K^+K^-$ contribute large branching fractions for $B^\pm \to \pi^\pm K^+K^-$ decays?

Abstract

We analyze the quasi-two-body decays $B^+\to\pi^+\rho(770,1450)^0 \to\pi^+ K^+K^-$ in the perturbative QCD approach. The results in this work do not support that large branching fractions contributed by the resonances $\rho(770,1450)^0$ in the $B^\pm \to \pi^\pm K^+K^-$ decays. The virtual contribution for $K^+K^-$ from the tail of the resonance $\rho(770)^0$ which has been ignored in the experimental studies is about $1.5$ times of the $\rho(1450)^0 \to K^+K^-$ contribution, with the predicted branching fractions ${\mathcal B}_v=(1.31\pm0.27)\times10^{-7}$ and ${\mathcal B}=(8.96\pm2.61)\times10^{-8}$, respectively, for these two subprocesses in the $B^\pm \to \pi^\pm K^+K^-$ decays. The absence of $\rho(770)^0\to K^+K^-$ for the decay amplitude of a three-body hadronic $B$ decay involving charged kaon pair could probably result in a larger proportion for the contribution from the resonance $\rho(1450)^0$ in the experimental analysis.