LAUSR

We analyze the quasi-two-body decays B+→π+ρ(770,1450)0→π+K+K- in the perturbative QCD approach. The results in this work do not support that large branching fractions contributed by the resonances ρ(770,1450)0 in the B±→π±K+K- decays. The virtual contribution for K+K- from the tail of the resonance ρ(770)0 which has been ignored in the experimental studies is about 1.5 times of the ρ(1450)0→K+K- contribution, with the predicted branching fractions Bv=(1.31±0.27)×10-7 and B=(8.96±2.61)×10-8, respectively, for these two subprocesses in the B±→π±K+K- decays. The absence of ρ(770)0→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 ρ(1450)0 in experimental analysis.