Branching fractions and CP asymmetries of the quasi-two-body decays in Bs→K0(K¯ 0) K±π∓ within PQCD approach

Motivated by the first untagged decay-time-integrated amplitude analysis of B_s→K_SK^∓π^± decays performed by LHCb collaboration, where the decay amplitudes are modeled to contain the resonant contributions from intermediate resonances K^∗(892 ) , K₀^∗(1430 ) and K₂^∗(1430 ) , we comprehensively investigate the quasi-two-body decays in the three-body processes [inline-graphic not available: see fulltext], and calculate the branching fractions and the time-dependent CP asymmetries within the perturbative QCD approach based on the k_T factorization. In the quasi-two-body space region the calculated branching fractions with the considered intermediate resonances are in good agreement with the experimental results of LHCb by adopting proper K π pair wave function, describing the interaction between the kaon and pion in the K π pair. Furthermore, within the obtained branching fractions of the quasi-two-body decays, we also calculate the branching fractions of the corresponding two-body decays, and the results consist with the LHCb measurements and the earlier studies within errors. For these considered decays, since the final states are not flavour-specific, the time-dependent CP could be measured. We then calculate six CP-violation observables, which can be tested in the ongoing LHCb experiment.