Study of the decays B\u3csup\u3e0\u3c/sup\u3e→D(*)\u3csup\u3e+\u3c/sup\u3eD(*)\u3csup\u3e-\u3c/sup\u3e

The decays B →D* D* , B →D*±D∓ and B →D D are studied in 9.7 X 10 γ(4S)→BB̄ decays accumulated with the CLEO detector. We determine B(B →D* D* ) = (9.9 [stat]±1.2[syst]) X 10 and limit B(B →D* D )\u3c6.3X10 and B(B →D D )\u3c9.4 X 10 at 90% confidence level (C.L.). We also perform the first angular analysis of the B →D* D* decay and determine that the CP-even fraction of the final state is greater than 0.11 at 90% C.L. Future measurements of the time dependence of these decays may be useful for the investigation of CP violation in neutral B meson decays. ©2000 The American Physical Society. 0 + - 0 0 + - 6 0 + - +4.2 -4 0 ± ∓ -4 0 + - -4 0 + - -3.