Photon events with missing energy at \(\sqrt{s} =\)183 to 189 GeV

  • The DELPHI Collaboration
  • P. Abreu et al.
Experimental physics

DOI: 10.1007/s100520000434

Cite this article as:
The DELPHI Collaboration & Abreu et al., P. Eur. Phys. J. C (2000) 17: 53. doi:10.1007/s100520000434


The production of single photons has been studied in the reaction \(e^+e^-\rightarrow\gamma+invisible particles\) at centre-of-mass energies of 183 GeV and 189 GeV. A previously published analysis of events with multi-photon final states accompanied by missing energy has been updated with 189 GeV data. The data were collected with the DELPHI detector and correspond to integrated luminosities of about 51 pb\(^{-1}\) and 158 pb\(^{-1}\) at the two energies. The number of light neutrino families is measured to be \(2.84\pm0.15(stat)\pm0.14(syst)\). The absence of an excess of events beyond that expected from Standard Model processes is used to set limits on new physics as described by supersymmetric and composite models. A limit on the gravitational scale is also determined.

Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • The DELPHI Collaboration
  • P. Abreu et al.
    • 1
  1. 1.LIP, IST, FCUL – Av. Elias Garcia, 14-1°, 1000 Lisboa Codex, PortugalPT

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