First measurement of the double-inclusive B/B hadron energy distribution in e+e− annihilations, and of angle-dependent moments of the B and B energies

The authors have made the first measurement of the double-inclusive B/{bar B} energy distribution in e{sup +}e{sup -} annihilations, using a sample of 400,000 hadronic Z{sup 0}-decay events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct B/{bar B}-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used to calculate the B energies in this novel technique. They measured the B/{bar B} energies with good efficiency and resolution over the full kinematic range. They measured moments of the scaled energies of the B and {bar B} hadrons vs. the opening angle between them. By comparing these results with perturbative QCD predictions they tested the ansatz of factorization in heavy-quark production. A recent next-to-leading order calculation reproduces the data.