Quasi-two-body decays $B_{(s)}\to K^{\ast }(892)h\to K\pi h$ in perturbative QCD approach

Abstract

We extend our recent works on the $P$-wave two-pion resonant contributions to the kaon-pion cases in the hadronic charmless $B$ meson decays by employing the perturbative QCD approach. The concerned decay modes are analysed in the quasi-two-body framework by parameterizing the kaon-pion distribution amplitude ${\Phi }_{K\pi }^{\mathrm{P}}$, which contains the final state interactions between the kaon and pion in the resonant region. The relativistic Breit-Wigner formula for the $P$-wave resonant state $K^{\ast }(892)$ is adopted to parameterize the time-like form factor $F_{K\pi }$. We calculate the $CP$-averaged branching ratios and direct $CP$-violating asymmetries of the quasi-two-body decays $B_{(s)}\to K^{\ast }(892)h\to K\pi h$, with $h=(\pi ,K)$, in this work. It is shown that the agreement of theoretical results with the experimental data can be achieved, through which Gegenbauer moments of the $P$-wave kaon-pion distribution amplitudes are determined. The predictions in this work will be tested by the precise data from the LHCb and the future Belle II experiments.

Comments: 13 pages, 1 figure. arXiv admin note: text overlap with arXiv:1807.02641