B-decay Charm Counting Via Topological Vertexing

We present a new measurement of the branching fractions of B hadrons 
decaying to 0, 1, and 2 charm hadrons, with a novel vertexing analysis.   
The measurement is performed on a sample of 350,000 Z's collected during 
the SLD/SLC 97-98 run.  The analysis takes advantage of the excellent 
vertexing resolution of the VXD3, a pixel-based CCD vertex detector, 
which allows the separation of B and cascade D decay vertices. Analysis 
of the decay length distributions for each of the 1-, 2-, and 3-vertex 
topologies allows the extraction of the inclusive branching fractions.  
The statistical errors for the 1, 2, and 3 charm branching fractions are 
expected to be, respectively, 0.013, 0.025, and 0.016.