B-D(0)(T)-]DPP TIME-DEPENDENT DALITZ PLOTS, CP-VIOLATING ANGLES 2-BETA, 2-BETA+GAMMA, AND DISCRETE AMBIGUITIES

We study CP-violation in resonant three-body B-d --> DPP decays, where PP stands for either (D) over bar pi, (D) over bar K-S, pi pi or pi K -S. Analogously to the B-d --> 3 pi channel and the extraction of 2 al pha, the first three channels are shown to measure cos2 beta in additi on to sin2 beta, thus allowing to resolve the beta --> pi/2 - beta amb iguity, while the D pi K-S final state leads to a measurement of 2 bet a + gamma. As cos2 beta and cos(2 beta + gamma) are CP-conserving quan tities, their determination is possible without tagging the flavor of the B-d meson. The B-d(o)(t) --> D+D- pi(o) channel via the interferen ce between D* orbitally excited resonances is taken as an example, al though this Cabibbo-suppressed decay suffers from irreducible penguin uncertainties. Then two penguin-free and Cabibbo-dominant modes are pr oposed: B-d(o)(t) --> D+D-KS with the D-s* resonances, and B-d(o)(t) --> D-CP(o) pi(+)pi(-) with the D* plus the rho. Finally, the B-d(o)( t) --> D(+/-)pi(-/+)K(S) channel with the D-S* and K* resonances prov ides a new clean method to measure the unusual angle 2 beta + gamma. W e present in all cases a crude estimate of the number of cos2 beta (re spectively 2 beta + gamma) sensitive events. We show that this number is an increasing function of the resonance mass, a favorable situation compared to the more extensively studied three-pion Dalitz plot. Howe ver, the poor detection efficiency of the D mesons could pose a proble m. As an annex and speculative application of these Dalitz plot based methods, the penguin-dominated B-d(o)(t) --> KSKSKL decay also measure s 2 beta. (C) 1998 Elsevier Science B.V. All rights reserved.