A partial wave analysis of the decay D0 → KS0π+π−

Abstract Using the ARGUS detector at the DORIS-II electron-positron storage ring at DESY, we have investigated the exclusive decay D ∗+ → D 0 π + , D 0 → K S 0 π + π − . From a partial wave analysis of the KS0π+π− system we find that (71.8± 4.2 ± 3.0)% are D 0 → K ∗− π + and (22.7 ± 3.2 ± 0.9)% are D 0 → K 0 ϱ 0 with a relative phase of (−137 ± 7 ± 3)° between the channels. The remaining fraction can be described by several channels involving excited resonances, but not by a three-body phase space decay, thus giving first evidence for D0 decays into K 0 ∗ (1430) − π + , K 0 f 0 (1975), K 0 f 2 (1270) , and K 0 f 0 (1400) .