par Abreu, Pedro;Vander Velde, Catherine 
;Bertrand, Daniel ; [et al.]
Référence European Physical Journal C. Particles and Fields, 1, page (1-20)
Publication Publié, 1998
;Bertrand, Daniel ; [et al.]Référence European Physical Journal C. Particles and Fields, 1, page (1-20)
Publication Publié, 1998
Article révisé par les pairs
| Résumé : | An update of the searches for charginos and neutralinos in DELPHI is presented, based mainly on recent data collected at centre-of-mass energies of 161 GeV and 172 GeV. No signal is found. For a sneutrino with mass above 300 GeV/c2 and a mass difference between the chargino and the lightest neutralino above 10 GeV/c2, the lower limit at 95% confidence level on the chargino mass ranges from 84.3 GeV/c2 to the kinematical limit (86.0 GeV/c2), depending on the mixing parameters. The limit decreases for lower chargino-neutralino mass differences. The limit in the case of a light sneutrino is 67.6 GeV/c2, provided that that there is no light sneutrino with a mass within 10 GeV/c2 below the chargino mass. Upper limits on neutralino pair production cross-sections of about a picobarn are derived. The (μ, M2) domain excluded in the MSSM-GUT scenario is determined by combining the neutralino and chargino searches. These results imply a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 24.9 GeV/c2 for tanβ ≥ 1. The search has also been extended to the case where the lightest neutralino is unstable and decays into a photon and a gravitino. |
