Abstract:

This talk describes the first Run II measurement of b quark fragmentation into Bd, Bu, Bs and Lambda_b using semileptonic B decays reconstructed in 360 pb-1 of data taken with the CDF detector. The fragmentation fractions are measured for an effective B hadron pT threshold of 7 GeV/c. The fragmentation fraction of B+ relative to B0 fraction and the fragmentation fraction of Bs relative to the B+ and B0 fractions are measured to be consistent with world averages, while the fragmentation fraction of Lambda_b relative to the B+ and B0 fractions is approximately 2 sigma higher than previous LEP results.