Inst High Energy Phys, Beijing 100039, Peoples R China
; CCAST, World Lab, Beijing 100080, Peoples R China
; Inst Theoret Phys, Beijing 100080, Peoples R China
; Ctr Theoret Nucl Phys, Natl Lab Heavy Ion Accelerator, Lanzhou 730000, Peoples R China
We generalize our previous work on pipi scattering to Kpi scattering, and reanalyze the experiment data for Kpi scattering below 1.6 GeV. Without any free parameter, we explain the Kpi I=3/2 S-wave phase shift very well by using t-channel rho and u-channel K* meson exchange. With the t-channel and u-channel meson exchange fixed as the background term, we fit the Kpi I=1/2 S-wave data of the LASS experiment quite well by introducing one or two s-channel resonances. It is found that there is only one s-channel resonance between the Kpi threshold and 1.6 GeV, i.e., K-0*(1430) with a mass around 1438-1486 MeV and a width of about 346 MeV, while the t-channel rho exchange gives a pole at (450-480i) MeV for the amplitude, rather uncertain due to the limitations of the approach used.