CP violation and final state interactions in $B \to K \pi\pi$ decays

3 pages, contribution to International Europhysics Conference on High Energy Physics HEP 2007, Manchester (England), July 19-25, 2007International audienceEffects of CP violation and of final state interactions between pairs of pseudoscalar mesons are studied in three-body B+, B-, B0 and antiB0 decays into K pi pi. An alternative approach to the isobar model for three-body B decays is proposed. It is based on the QCD factorization approximation and the knowledge of the meson-meson form factors. Some phenomenological charming penguin amplitudes are needed to describe the branching fractions, direct CP asymmetries of the quasi-two-body B --> K*(892) pi and B --> K0*(1430) pi decays as well as the K pi effective mass and the helicity angle distributions. The experimental branching fractions for the B --> K0*(1430) pi decay, obtained by the Belle and BaBar collaborations using the isobar model, are larger than our predictions by about 52 per cent