Measurements of B ---> D(*)(S)+ D+(*) branching fractions

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