Radiative B meson decays into Kπγ and Kππγ final states

We report observations of radiative B meson decays into the K + π - γ and K + π - π + γ final states. In the B 0 → K + π - γ channel, we present evidence for decays via an intermediate tensor meson state with a branching fraction of B(B 0 → K * 2 (1430) 0 γ) = [1.3 ′ 0.5(stat) ′ 0.1(syst)] × 10 - 5 . We measure the branching fraction B(B + → K + π - π + γ) = [2.4 ′ 0.5(stat) + 0 . 4 - 0 . 2 (syst)] × 10 - 5 , in which the B + → K* 0 π + γ and B + → K + ρ 0 γ channels dominate. The analysis is based on a data set of 29.4 fb - 1 recorded by the Belle experiment at the KEKB collider.