Elsevier

Physics Letters B

Volume 237, Issue 1, 8 March 1990, Pages 136-146
Physics Letters B

Measurement of Z0 decays to hadrons, and a precise determination of the number of neutrino species

https://doi.org/10.1016/0370-2693(90)90476-MGet rights and content

Abstract

We have made a precise measurement of the cross section for e+e→Z0→hadrons with the L3 detector at LEP, covering the s range from 88.28 to 95.04 GeV. From a fit to the Z0 mass, total width, and the hadronic cross section to be MZ0=91.160 ± 0.024 (experiment) ±0.030(LEP) GeV, ΓZ0=2.539±0.054 GeV, and σh(MZ0)=29.5±0.7 nb. We also used the fit to the Z0 peak cross section and the width todetermine Γinvisible=0.548±0.029 GeV, which corresponds to 3.29±0.17 species of light neutrinos. The possibility of four or more neutrino flavors is thus ruled out at the 4σ confidence level.

References (18)

  • S.L. Glashow

    Nucl. Phys.

    (1961)
    S. Weinberg

    Phys. Rev. Lett.

    (1967)
    A. Salam
  • D. Decamp

    Phys. Lett. B

    (1989)
    M.Z. Akrawy

    Phys. Lett. B

    (1989)
    P. Aarnio

    Phys. Lett. B

    (1989)
  • D. Decamp

    Phys. Lett. B

    (1990)
  • Machine Group, LEP Division (CERN), private...
  • L3 Collab., B. Adeva et al., The construction of the L3 experiment, Nucl. Instrum. Methods, to be...
  • S. Jadach et al.

    BHLUMI

    (June 1988)
    see S. Jadach and B.F.L. Ward, preprint...R. Kleiss

    Z physics at LEP

  • R. Kleiss et al.

    Nucl. Phys. B

    (1981)
  • A. Borelli, M. Consoli, L. Maiani and R. Sisto, CERN preprint CERN-TH...
  • B. Adeva

    Phys. Lett. B

    (1989)
There are more references available in the full text version of this article.

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Supported by the German Bundesministerium für Forschung und Technologie.

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