Measurement of the absolute branching fractions B→Dπ, D*π, D**π with a missing mass method

We present branching fraction measurements of charged and neutral B decays to Dπ-, D*π-, and “D**”π- with a missing mass method, based on a sample of 231×10^6 Υ(4S)→BB̅ pairs collected by the BABAR detector at the PEP-II e+e- collider. One of the B mesons is fully reconstructed and the other one decays to a reconstructed charged π and a companion charmed meson identified by its recoil mass, inferred by kinematics. Here “D**” refers to the sum of all the nonstrange charm meson states with masses in the range 2.2–2.8  GeV/c2. We measure the branching fractions: B(B-→D0π-)=(4.49±0.21±0.23)×10-3, B(B-→D*0π-)=(5.13±0.22±0.28)×10-3, B(B-→“D**0”π-)=(5.50±0.52±1.04)×10-3, B(B̅ 0→D+π-)=(3.03±0.23±0.23)×10-3, B(B̅ 0→D*+π-)=(2.99±0.23±0.24)×10-3, B(B̅ 0→“D**+”π-)=(2.34±0.65±0.88)×10-3, and their ratios.