[en] Inclusive muon pair production by 225 GeV/c π⁺, π^- and proton beams incident upon carbon and tin targets was measured over a large range of kinematic variables (2m/sub μ/ < m/sub μμ < 10 GeV/c², 0< x/sub F/< 1, P/sub perpendicular/ < 4 GeV/c and /cos theta*/ < .8). The value of the invariant cross section E d⁴sigma/dm dx/sub F/ dp²/sub perpendicular/, is presented as a function of these variables. The vector mesons rho, Ω, psi, J and Psi' appear in the data along with apparently nonresonant μ-pairs. By looking for additional muons accompanying J → μ⁺μ^- events, a 1.0 percent upper limit on production of pairs of charmed particles in association with the J is obtained. Aspects of the continuum muon pair data are compared to Drell-Yan model calculations. The ratio of μ-pairs produced by π⁺ beam particles to μ-pairs produced by π^-beam particles supports electromagnetic production at high mass

[en] In search for new quark flavors, an excess of low thrust events containing muons is found for PETRA energies greater than 46.3 GeV. The muons in these events are quite isolated from hadronic energy as would be expected from pair production of massive quarks. Combining data from all 4 PETRA experiments, there are 14 events with thrust less than 0.8 and the cosine of the angle between the muons direction and the thrust axis less than 0.7. Based directly on measurements taken at lower energy, the expected number of evens is quite accurately predicted to be 2.4. The probability of a statistical fluctuation of this size or larger occurring in a given event selection is 3 x 10/sup -7/. Although these events are consistent with the production of a new quark flavor, the evidence is as yet insufficient to prove that this is the source. No excess of events is seen in the selection of low thrust events with isolated electrons where the sensitivity is substantially lower

[en] I review measurements of the electroweak interactions of leptons and quarks and searches for the source of symmetry breaking in high energy electron positron collisions at PETRA. The purely leptonic interactions, Bhabha scattering, muon pair production and tau pair production have been studied in detail. Experiments at PETRA have observed weak neutral current effects by measuring the foreward backward charge asymmetry in muon pair production to an accuracy of better than 2% at q² of approximately 1200 GeV². The data are interpreted in terms of sin²THETAsub(w) in the standard model and gsub(A), gsub(V) and C in more general model of electroweak interactions. Using measurements of R, we make a more accurate determination of sin²THETAsub(w) at high q². Technipions, charged Higgs particles and supersymmetric scalar particles have been searched for up to masses of 15 GeV. (orig.)

No abstract available

[en] I report on some of the more important results from high energy electron positron collisions at PETRA. These results come from the data collected over the last three years by five experiments: CELLO, JADE, MARK-J, PLUTO and TASSO. Topics include measurements of the electroweak interactions of leptons and quarks and searches for the source of electroweak symmetry breaking. The purely leptonic interactions, Bhabha scatering, muon pair production and tau pair production have been studied in detail. Experiments at PETRA have observed weak neutral current effects by measuring the forward backward charge asymmetry in muon pair production to an accuracy of better than 2% at q₂ of approximately 1200 GeV₂. The data are interpretted in terms of sin₂THETAsub(w) in the standard model and gsub(A), gsub(v) and C in more general models of electroweak interactions. Using measurements of R, we make a more accurate determination of sin₂THETAsub(w) at high q₂. Technipions, charged Higgs particles, and supersymmetric scalar particles have been searched for up to masses of 15 GeV. Quantum chromodynamics is found to be in excellent agreement with the distributions of three jet events and αsub(g) is measured using second order perturbative QCD calculations. (orig.)

[en] I will report on measurements of the electroweak interactions of leptons and quarks in high energy electron positron collisions concentrating on new data from PETRA which is not reported elsewhere at this conference. The purely leptonic interactions, Bhabha scattering, muon pair production and tau pair production have been studied in detail and the experiments at PETRA have observed weak neutral current effects for the first time in the measurement of the forward backward charge asymmetry in muon pair production at q²'s of around 1200 GeV². The data are interpreted in terms of values of sin²THETAsub(w) in the standard model and of gsub(A), gsub(V), and C in more general models of electroweak interactions. Using measurements of R, we make a more accurate determination of sin²THETAsub(w) at high q². The semileptonic branching ratio of B particle decay is measured as a preview of possible determination of the asymmetry in b and c quark production at high q². Finally, we look for structure in the fermions, e, μ, tau, and q by the study of their high q² interactions. (orig.)

[en] I review measurements of the electroweak interactions of leptons and quarks and searches for the source of symmetry breaking in high energy electron positron collisions at PETRA. The purely leptonic interactions, Bhabha scattering, muon pair production and tau pair production have been studied in detail. Experiments at PETRA have observed weak neutral current effects by measuring the foreward backward charge symmetry in muon pair production to an accuracy of better than 2% at q² of approximately 1200 GeV². The data are interpreted in terms of sin²THETA sub(w) in the standard model and g sub(A), g sub(V) and C in more general model of weak interactions. Using measurements of R, we make a more accurate determination of sin² THETA sub(w) at high q². Technipions, charged Higgs particles and supersymmetric scallar particles have been searched for up to masses of 15 GeV. (author)

[en] This paper discusses a search for new quark flavors in which an excess of low-thrust events containing muons has been found for PETRA energies greater than 46.3 GeV. The muons in these events are quite isolated from hadronic energy, as would be expected from pair production of massive quarks. This paper presents the results of combining data from 4 PETRA experiments. Conclusions are then offered

[en] Results from three PETRA experiments on e⁺e^- → e⁺e^- and e⁺e^- → μ⁺μ^- are presented. These are used to test for deviations of the photon propagator from 1/q² or for nonpointlike behavior of one of the particles γ, e or μ. Quantum electrodynamics is found to be valid down to distances of 4 x 10^-16 cm. (orig.)

[en] A summary of the highlights of high energy e/sup +/e/sup -/ interactions is presented including some new particle searches, the recent progress on QCD, and a new result which rules out the independent jet fragmentation model