Tests of QCD using Heavy Flavors at SLD

TL;DR

This paper reports on three analyses of heavy flavor production at SLD, comparing measurements of gluon spectra, g->bb rates, and B fragmentation functions with QCD predictions, setting limits on anomalous couplings.

Contribution

It provides new measurements of gluon energy spectra, g->bb rates, and B fragmentation functions using SLD data, with improved techniques and constraints on anomalous couplings.

Findings

Gluon energy spectrum agrees with perturbative QCD.

Set new limits on b quark's anomalous chromomagnetic coupling.

Measured B hadron energy distribution over full kinematic range.

Abstract

We present preliminary results on three SLD analyses: the gluon energy spectrum in 3-jet bbg events, the rate of g->bb, and the b fragmentation function in Z0 decays. The gluon energy spectrum, measured over the full kinematic range, is compared with perturbative QCD predictions. We set new 95% C.L. limits on the anomalous chromomagnetic coupling of the b quark: -0.09<kappa<0.06. The rate of g->bb is measured to be (3.07 +/- 0.71(stat) +/- 0.66(syst)) X 10^-3. The inclusive B hadron energy distribution in Z0 decays is measured for the first time over the full kinematic range, using a novel B hadron energy reconstruction technique. Several models of b fragmentation including JETSET + Peterson are excluded by the data. The average scaled B hadron energy of the weakly decaying B hadron is measured to be XB = 0.713 +/- 0.005(stat) +/- 0.007(syst) +/- 0.002 (model). All three measurements take advantage of the small and stable SLC interaction point as well as the excellent vertexing and tracking capabilities of the upgraded CCD-pixel vertex detector.