RECENT RESULTS ON e+ e- ANNIHILATION FROM PETRA
D. Cords · DESY (CERN, DESY, Fermilab, IHEP, and SLAC) · 1983
Over the past year the energy of PETRA has been steadily increased in order to extend the search for the top quark.Neither topponium bound states nor a threshold for open top production has been found below a c.m. energy of 43 GeV.The implication of.the measurement of R, the ratio of the hadronic to the point-like ~-pair cross section, on the determination of the strong coupling constant a 5 .isdiscussed.The analysis of jets reveals, that the primary hadron fragments are heavy, that the fragmentation function of heavy quarks c and b is hard, and that gluons tend to have a wider transverse momentum distribution than quarks.The search for exotic particles is reported as negative for new heavy leptons, for scalars like charged Higgs mesons or technipions and for supersymmetric particles.Mass limits are given.