Study of the Bs → ϕf0(980) → ϕ π+π− decay with perturbative QCD approach

Abstract

The rare cascade Bs → ϕf0(980) → ϕ π+π− decay is studied with the perturbative QCD approach based on the formula for the quasi two-body decay, where the two-pion pair originates from the S-wave resonant f0(980) state. It is found that with the introduction of the nonperturbative two-pion distribution amplitudes and the Flatté parameterization of the scalar form factor for the f0(980) resonance, the branching ratio in the mass range 400 MeV < m(π+π−) < 1600 MeV is = , where the uncertainties come from the parameter aππ of the two-pion distribution amplitudes, the b quark mass mb, and the Cabibbo–Kobayashi–Maskawa factors, respectively. This result agrees with the recent LHCb measurement within uncertainties, = , where the errors are statistical, systematic and from the normalization, respectively.