Results on jets, QCD and lepton production from the MARK J

MARK J results on the properties of three jet events, on lepton pair production, and on a search for new heavy charged leptons in e+e- annihilation are presented. Analysis of the energy flow pattern of hadronic events shows that the production rate and the shape of flat three jet events are in excellent agreement with the predictions of QCD, and that the planar events in e+e-→ hadrons have three well separated collimated jets. By use of the triplicity method we show that the energy of individual jets and the angles between the jets agree with the predictions of QCD. MARK J data on e+e-→e+e-, μ+μ- and tau+tau- are also presented. A search for the production of a new heavy lepton and for the spin zero supersymmetric partners of the muon rules out the existence of a new heavy lepton below 16 GeV or a supersymmetric scalar particle below 15 GeV