Study of three-body charmless B decays

Abstract

We report on a study of three-body charmless decays B+ => K+h+h-$ based on a 29.1 fb^{-1} data sample collected with the Belle detector. With no assumptions on the intermediate mechanisms, the following three-body branching fractions have been measured for the first time: Br(B+ => K+pi-pi+) = (55.6\pm5.8\pm7.7)x10^{-6} and Br(B+ => K+K-K+) = (35.3\pm3.7\pm4.5)x10^{-6}. We present the first observation of the decay B+ => f_0(980)K+ with a branching fraction product of Br(B+ => f_0(980)K+)xBr(f_0(980) => \pi+\pi-)= (9.6^{+2.5+1.5+3.4}_{-2.3-1.5-0.8})x10^{-6}. This is the first reported example of a B meson decay to a scalar pseudoscalar final state. We also report the first observation of B+ => K*(892)^0 pi+ decay with a branching fraction of Br(B+ => K*(892)^0 pi+) = (19.4^{+4.2+2.1+3.5}_{-3.9-2.1-6.8})x10^{-6}.