Charm production in B meson decay

We have studied the production of charmed particles in decays of B mesons from the Upsilon 4S resonance. We report improved measurements of B decay to charmed mesons, and present new evidence that charmed baryons are produced in B decay. The yield of charmed particles is used to derive a limit on how often the b quark couples to the c quark compared to the u quark; the data are consistent with 100% b to c. The results are compared with measurements from other experiments and with other techniques for estimating the b-to-u and b-to-c fractions.