Study of quasi-two-body B(s)→φ(f0(980)/f2(1270)→)ππ decays in perturbative QCD approach

In 2017, LHCb collaboration reported their first observation of the rare decays Bs -> phi (f0(980)/f2(1270)->)pi+pi- and the evidence of B0 -> phi (f0(980)/f2(1270)->)pi+pi-. Motivated by this, we study these quasi-two-body decays in the perturbative QCD approach. The branching fractions, CP asymmetries and the polarization fractions are calculated. We find that within the appropriate two-meson wave functions, the calculated branching fractions are in agreement with the measurements of LHCb. Based on the narrow-width approximation, We also calculate the branching fractions of the quasi-two-body Bd,s -> phi (f0(980)/f2(1270)->)pi 0 pi 0 and Bd,s -> phi (f2(1270)-> )K+K-, and hope the predictions to be tested in the ongoing LHCb and Belle II experiments. Moreover, the processes Bd,s -> phi f2(1270) are also analyzed under the approximation. We note that the CP asymmetries of these decays are very small, because these decays are either penguin dominant or pure penguin processes.

Automated summary

The study shows that the calculated results in the perturbative QCD approach are consistent with experimental measurements, indicating the reliability of observations of these quasi-two-body decays. In addition, branching fractions of other quasi-two-body decays were also calculated based on the narrow-width approximation, with hopes of validation in future experiments.