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Tests of the standard model and constraints on new physics from measurements of fermion-pair production at 130–172 GeV at LEP

  • The OPAL Collaboration
  • K. Ackerstaff et al.
Experimental physics

Abstract.

Production of events with hadronic and leptonic final states has been measured in \({\rm e^+e^-}\) collisions at centre-of-mass energies of 130–172 GeV, using the OPAL detector at LEP. Cross-sections and leptonic forward-backward asymmetries are presented, both including and excluding the dominant production of radiative Z\(\gamma\) events, and compared to Standard Model expectations. The ratio \(R_{\rm b}\) of the cross-section for \({\rm b\bar b}\) production to the hadronic cross-section has been measured. In a model-independent fit to the Z lineshape, the data have been used to obtain an improved precision on the measurement of \(\gamma\)-Z interference. The energy dependence of \(\alpha_{\mathrm{em}}\) has been investigated. The measurements have also been used to obtain limits on extensions of the Standard Model described by effective four-fermion contact interactions, to search for \(t\)-channel contributions from new massive particles and to place limits on gaugino pair production with subsequent decay of the gaugino into a light gluino and a quark pair.

Keywords

Pair Production Energy Dependence Massive Particle Opal Detector Contact Interaction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • The OPAL Collaboration
  • K. Ackerstaff et al.
    • 1
  1. 1. CERN, European Organisation for Particle Physics, CH-1211 Geneva 23, Switzerland CH

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