Professor Brian Foster OBE, FRS

Abstract:

The forward-backward asymmetry in the reaction e+e-→bb has been determined at centre of mass energies near 35 GeV using the TASSO detector. We report results from three different methods. The combined result of the measurements is {Mathematical expression} ignoring {Mathematical expression} mixing. Taking mixing into account leads to a corrected asymmetry of {Mathematical expression}. The axial vector coupling constant of the b quark as calculated from the corrected asymmetry is ab=-1.2±0.5 to be compared with the value abSM=-1 from the standard model. © 1990 Springer-Verlag.

Abstract:

The full TASSO data have been used to study the orientation of three-jet events in e+e- annihilation. The polar angle distributions of the normal to the three-jet plane as well as the polar angle distribution of the most energetic jet have been measured as a function of the thrust cut-off used to select the three-jet sample. The data corrected for radiation and detector effects are compared to QCD predictions and fair agreement is found. As a consistency check we also present measurements of the azimuthal correlations between the lepton and hadron planes. A significant azimuthal dependence is found, consistent again with the QCD predictions. © 1990 Springer-Verlag.

Abstract:

Jet properties in e+e- annihilation at center of mass energies of 14, 22, 35 and 43.7 GeV were studied with the data collected in the TASSO detector at PETRA, using the same evaluation procedures for all the energies. The total hadronic cross section ratio for the center of mass energy interval 39-47 GeV was determined to be ℛ=4.11±0.05 (stat)±0.18(syst.) at {Mathematical expression} GeV. Corrected distributions of global shape variables are presented as well as the inclusive charged particle distributions for scaled momentum and transverse momentum. The center of mass energy evolution of the average sphericity, thrust, aplanarity and particle momentum is shown. © 1990 Springer-Verlag.

Abstract:

Production of charmed mesons in γγ-interactions at PETRA energies has been observed in the TASSO detector. Cross sections for inclusive D*± and {Mathematical expression} production have been measured. Neutral and charged meson pairs are estimated to be produced with comparable cross sections, and their sum seems to account for a sizeable fraction of σtot(γγ→hadrons) near the {Mathematical expression} threshold. © 1990 Springer-Verlag.

Abstract:

The full TASSO data have been used to study the inclusive production of strange mesons in e+e- annihilations. Differential and total cross sections have been measured in the centre of mass energy range 14 to 44 GeV for K0, {Mathematical expression} and 34.5 to 44 GeV for K*± (892). We have investigated the strange meson production properties in jets by studying the rapidity and pt2 distributions as well as the evolution of the multiplicities as a function of the event sphericity. We find no evidence that the strange meson yields increase with increasing sphericity faster than the total charged multiplicity. © 1990 Springer-Verlag.