Branching fractions and CP asymmetries of the quasi-two-body decays in B_{s} rightarrow K^0({overline{K}}^0)K^pm pi ^mp within PQCD approach

Abstract

Motivated by the first untagged decay-time-integrated amplitude analysis of B_s rightarrow K_SK^{mp }pi ^{pm } decays performed by LHCb collaboration, where the decay amplitudes are modeled to contain the resonant contributions from intermediate resonances K^*(892), K_0^*(1430) and K_2^*(1430), we comprehensively investigate the quasi-two-body decays in the three-body processes , 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 Kpi pair wave function, describing the interaction between the kaon and pion in the Kpi 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.