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Search for chargino and neutralino production at \(\sqrt{s} = 189\) GeV at LEP

  • The OPAL Collaboration
  • G. Abbiendi et al.
Experimental physics
  • 45 Downloads

Abstract.

A search for charginos and neutralinos, predicted by supersymmetric theories, is performed using a data sample of 182.1 pb\(^{-1}\) taken at a centre-of-mass energy of 189 GeV with the OPAL detector at LEP. No evidence for chargino or neutralino production is found. Upper limits on chargino and neutralino pair production (\(\tilde{\chi}^+_1 \tilde{\chi}^-_1\), \(\tilde{\chi}^0 _1 \tilde{\chi}^0 _2\)) cross-sections are obtained as a function of the chargino mass (\(m_{\tilde{\chi}^\pm_1}\)), the lightest neutralino mass (\(m_{\tilde{\chi}^0 _1}\)) and the second lightest neutralino mass (\(m_{\tilde{\chi}^0 _2}\)). Within the Constrained Minimal Supersymmetric Standard Model framework, and for \(m_{\tilde{\chi}^\pm_1} - m_{\tilde{\chi}^0 _1} \geq 5\) GeV, the 95% confidence level lower limits on \(m_{\tilde{\chi}^\pm_1}\) are 93.6 GeV for \(\tan \beta = 1.5\) and 94.1 GeV for \(\tan \beta = 35\). These limits are obtained assuming a universal scalar mass \(m_0 \geq\) 500 GeV. The corresponding limits for all \(m_0\) are 78.0 and 71.7 GeV. The 95% confidence level lower limits on the lightest neutralino mass, valid for any value of \(\tan \beta\) are 32.8 GeV for \(m_0 \geq 500\) GeV and 31.6 GeV for all \(m_0\).

Keywords

Confidence Level Pair Production Minimal Supersymmetric Standard Model Model Framework Scalar Mass 
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 2000

Authors and Affiliations

  • The OPAL Collaboration
  • G. Abbiendi et al.
    • 1
  1. 1.Dipartimento di Fisica dell' Università di Bologna and INFN, 40126 Bologna, ItalyIT

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