Measurement of B-->D(*)+sD*(*) branching fractions

This article describes improved measurements by CLEO of the B⁰-->D⁺_sD^*- and B⁰-->D^*+_sD^*- branching fractions, and first evidence for the decay B⁺-->D^(*)+_sD¯^**0, where D¯^**0 represents the sum of the D¯₁(2420)⁰, D¯^*₂(2460)⁰, and D¯₁(j=1/2)⁰ L=1 charm meson states. Also reported is the first measurement of the D^*+_s polarization in the decay B⁰-->D^*+_sD^*-. A partial reconstruction technique, employing only the fully reconstructed D⁺_s and slow pion π^-_s from the D^*--->D¯⁰π^-_s decay, enhances sensitivity. The observed branching fractions are B(B⁰-->D⁺_sD^*-)=(1.10+/-0.18+/-0.10+/-0.28)%, B(B⁰-->D^*+_sD^*-)=(1.82+/-0.37+/-0.24+/-0.46)%, and B(B⁺-->D^(*)+_sD¯^**0)=(2.73+/-0.78+/-0.48+/-0.68)%, where the first error is statistical, the second systematic, and the third is the uncertainty in the D⁺_s-->φπ⁺ branching fraction. The measured D^*+_s longitudinal polarization, Γ_L/Γ=(50.6+/-13.9+/-3.6)%, is consistent with the factorization prediction of 54%.