Journal Article

Search for charginos, neutralinos and gravitinos at LEP

Dracos, M., De Min, A., Castillo Gimenez, M. V., Kurvinen, K., Ruiz, A., Renton, R. B., Parzefall, U., Lutz, P., Zevgolatakos, E., Normand, A., Apel, W -D., Gunther, M., Chaussard, L., Van Damlo, P., Hrubec, J., Marechal, B., Ueberschaer, B., Strauss, J., Toet, D. Z., Augustinus, A., Kucewicz, W., Allport, P. P., Booth, P. S. L., Strub, R., Cossutti, F., Meyer, W. T., Galloni, A., Laktineh, I., Andersson, P., Bonivento, W., Koratzinos, M., Lapin, V., Margoni, M., Sosnowski, R., Resvanis, L. K., Fulda-Quenzer, F., Hultqvist, K., Benvenuti, A. C., De Angelis, A., Marco, J., Bianchi, F., Gazis, E. N., Lyons, L., Sadovsky, A., Martinez-Vidal, F., Hessing, T. L., Joram, C., Moeller, R., Stapnes, S., Tonazzo, A., Ferrer, A., Holt, P. J., Grosdidier, G., Rinaudo, G., Skaali, T. B., Mariotti, C., Pierre, F., Mirabito, L., Dahm, J., Gele, D., Uvarov, V., Souza-Santos, D., Ruhlmann-Kleider, V., Abreu, P., Åsman, B., Billoir, P., Pain, R., Garcia, C., Stanic, S., Alemany, R., Sedykh, Y., De Boer, W., Matorras, F., Poropat, P., Engel, J -P., Elsing, M., Heuser, J. -M., Lesiak, T., Della Ricca, G., Cortina, E., Lemonne, J., Higon, E., Fokitis, E., Lopez, J. M., A

1998

Overview

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 tanß >- 1. The search has also been extended to the case where the lightest neutralino is unstable and decays into a photon and a gravitino. 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 tanß >- 1. The search has also been extended to the case where the lightest neutralino is unstable and decays into a photon and a gravitino.

• Publisher: Springer Nature B.V
• Subject: Confidence intervals / Fermions / Gravitinos / Pair production / Photons / Searching