Experimental study of the orientation of three-jet events ine⁺e⁻ annihilation at PETRA

The full TASSO data have been used to study the orientation of three-jet events ine+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.