36 Result(s)
within
Ch. berger
English
Quantum Field Theories, String Theory
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Article
Tests of the standard model with lepton pair production ine + e − reactions
The differential cross section of the reactione +e−→e +e− at a c.m. energy of 34.7 GeV has been measured. The result, together with our previously measurede +e−→α +α− data, are compared with the standard model pr...
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Article
Sterman-Weinberg jets and energy flow ine + e − annihilation at CM energies between 9.4 and 35 GeV
The Sterman-Weinberg 2-jet cross section is measured from the hadron energy flow using the thrust axis to define the axis of the jet cone. The results are compared with first order QCD predictions. Deviations ...
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Article
Tagged two photon production of muon Pairs
The processe + e −→e + e − μ+μ− has been studied using the PLUTO detector at PETRA. The data agree well with QED calculations to order α4. Comparison is also made with the predicted leptonic structure function of...
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Article
Study of the reactionγγ→2π +2π − π 0 γγ→ωω andγγ→ρ 0 ω
A search for the reactionsγγ→ωω andγγ→ρ 0 ω has been carried out at an averagee + e − CM energy of 34.6 GeV with an integrated luminosity of 45 pb−1. Upper limits are set for these two channels over the γγ CM Ene...
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Article
Measurements of Tau-Lepton production and decay
We have studied 419 τ pair events produced in the reactione + e −→τ+ τ− at a c.m. energy of 34.6 GeV. We measure the cross section and angular distribution, as well as the decay branching ratios. The production c...
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Article
TheQ 2 and transverse momentum dependence of jet production in photon-photon interactions
We present an experimental study of jetproduction in photon-photon interactions for 0.1≲Q 2≲120 GeV2 and jet transverse momentum,p T , up to 5 Ge...
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Article
Pion pair production in photon-photon interactions
The processγγπ+π− has been measured with complete particle identification. Cross-sections are presented from near threshold up to the region of thef(1270). In the mass range 0.5–0.7 GeV, crosssections are lower t...
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Article
A measurement of theQ 2 andW dependence of the γγ total cross section for hadron production
A measurement of the γγ total cross section, σγγ(Q 2 W), is presented for theQ 2 range 0.1 to 100 GeV2, and for the massW of the hadronic final state between 1.5 and 10 GeV. The dependence of σγγ on bothQ 2 andW ...
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Article
Measruement of transverse momenta ine + e − annihilation jets at PETRA
Transverse particle momenta have been measured ine + e − annihilation into hadrons at c.m. energies between 9.4 and 31.6 GeV. The data are fully corrected for detector effects and radiation in the initial state. ...
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Article
Energy moments for quark jets at PETRA
Measurements of energy moments for single quark jets at c.m. energies between 12 and 31.6 GeV are presented. The data, corrected for detector effects and initial state radiation, are compared to QCD prediction...
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Article
Measurement of the muon pair asymmetry ine + e − annihilation at \(\sqrt s = 34.7GeV\)
The reactione + e −→μ + μ − has been studied with the PLUTO detector at the c.m. energy of 34.7 GeV, based on an integrated luminosity of 46 pb−1. The total cross section agrees with QED predictions, and the corr...
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Article
Energy dependence of jet measures ine + e − annihilation
The jet character of the hadronic final states produced ine + e − annihilations is studied in terms of jet measures such as thrust, sphericity, jet opening angle and jet masses, in the energy range 7.7 to 31.6 Ge...
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Article
Experimental test of electroweak effects at PETRA energies
The differential cross sections for Bhabha scattering and μ pair production, and the total τ pair cross section as measured by the PLUTO detector at PETRA, have been analyzed to extract information on the weak...
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Article
Topology of the Υ-decay
Multihadron events resulting frome + e − annihilation at the Υ-resonance are analysed with respect to lowest order QCD which predicts a dominant Υ decay into three vector gluons. Smearing effects due to the gluon...
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Article
Test of QED in the reactionse + e −→e + e − ande + e −→μ + μ − at CMS energies from 9.4 to 31.6 GeV
We have measured Bhabha scattering at cms energies of 9.4, 13, 17, 22, 27.5, 30.0, and 31.6 GeV and the reactione + e -→μ + μ - at 9.4 GeV. The experiment covers spacelike momentum transfers up to −850 GeV2 and t...
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Article
Measurement of leptonic branching ratios of the Γ(9.46)
The electronic width Γ ee and the muonic branching ratioB μμ =Γ μμ /Γtot of the Γ(9.46) have been measured a...
