Eur Phys J C (2004) 33: s485-s487
https://doi.org/10.1140/epjcd/s2004-03-1661-y

PS04 Hard QCD

First Measurement of the Double-inclusive Hadron Energy Distribution in e⁺e^– Annihilations, and of Angle-Dependent Moments of the B and

Queen Mary, University of London, Mile End Rd., London E1 4NS, England

Received: 17 November 2003
Accepted: 20 January 2004
Published online: 13 February 2004

Abstract

We have made the first measurement of the double-inclusive B/ energy distribution in e⁺e^– annihilations, using a sample of 400,000 hadronic Z 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/-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. We measured the B/ energies with good efficiency and resolution over the full kinematic range. We measured moments of the scaled energies of the B and hadrons vs. the opening angle between them. By comparing these results with perturbative QCD predictions we tested the ansatz of factorisation in heavy-quark production. A recent next-to-leading order calculation reproduces the data.