Abstract
We have searched for neutralinos produced via the reactions e + e - → χχ′ and e + e - → χ′χ′, where the next-to lightest neutralino, χ′, decays into the lightest neutralino, χ, and either a photon or a fermion pair. Based on 1.8 × 10 6 hadronic Z decays collected with the L3 detector at LEP, no signal has been observed. We present upper limits of a few times 10 -5 on the branching ratios Z → χχ′ and Z → χ′χ′. In the framework of the Minimial Supersymmetric Standard Model, we exclude a lightest χ with m χ less than 18 GeV, if either tan β > 2 or the gluino mass m ≈g > 100 GeV.
| Original language | English |
|---|---|
| Pages (from-to) | 109-119 |
| Number of pages | 11 |
| Journal | Physics Letters B |
| Volume | 350 |
| Issue number | 1 |
| DOIs | |
| State | Published - May 4 1995 |
Funding
B I. Physikalisches Institut, RWTH, D-52056 Aachen, FRG ’ Ill. Physikalisches Institut, RWTH, D-52056 Aachen, FRG 1 b National Institute for High Energy Physics, NIKHEF, NL-1009 DB Amsterdam, The Netheriands c University of Michigan, Ann Arbor, MI 48109, USA d Laboratoire d’Annecy-le-Vieux de Physique des Patti&es, LAPP,IN2P3-CNRS, BP 110, F-74941 Annecy-le-Vieux CEDEX, France c Johns Hopkins University, Baltimore, MD 21218, USA f Instituie of High Energy Physics, IHEP, loo039 Beijing, Chino s Humboldr Universily D-10099 Berlin, FRG h INFN-Sezione di Bologrq I-40126 Bologna, Italy i Tata Institute of Funaknen.tal Research, Bombay 400 005, India j Boston University Boston, MA 02215, USA k Northeastern University, Boston, MA 02115, US4 ’ Institute ofAtomic Physics and University of Bucharest, R-76900 Bucharest, Romania m Central Research Institute for Physics of the Hungarian Academy of Sciences, H-1525 Budapest 114, Hungary 2 n Harvard University, Cambridge, MA 02139, USA O Massachusetts Institute of Technology, Cambridge, M4 02139, USA P INFN Sezione di Firenze and University of Florence, I-50125 Florence, Italy 9 European Laboratory for Particle Physics, CERN, CH-1211 Geneva 23, Switzerland r World Laboratory, FBLJA Project, CH-1211 Geneva 23, Switzerland s University of Geneva, CH-1211 Geneva 4, Switzerland t Chinese University of Science and Technology, USTC, Hefei, Anhui 230 029, China u SEFT, Research Institute for High Energy Physics, P.O. Box 9, SF-00014 Helsinki, Finland v University of Lausanne, CH-1015 Lausanne, Switzerland w Los Alamos National Laboratory, Los Alamos, NM 87544, USA x institut de Physique Nucliaire de Lyon, iN2P3-CNRS, Universite’ Claude Bernard, F-69622 Villeurbanne Cedex, France Y Centro a’e investigaciones Energeticas, Medioambientales y Tecnologicas, CIEMXT, E-28040 Madrid, Spain 3 z INFN-Sezione di Milano, i-20133 Milan, Italy aa institute of Theoretical and Experimental Physics, ITEP, Moscow, Russia ab INFN-Sezione di Napoli and University of Naples, I-80125 Naples, Italy a’ Department of Natural Sciences, University of Cyprus, Nicosia, Cyprus a’ University of Nymegen and NIKHEF, NL-6525 ED Nymegen, The Netherlands ae Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA af California institute of Technology, Pasadena, CA 91125, USA BgI NFN-Sezione di Perugia and Universiti Degli Studi di Perugia, i-06100 Perugia, Italy ah Carnegie Mellon University, Pittsburgh, PA 15213, USA a’ Princeton University, Princeton, NJ 08544, USA a’ INFN-Sezione di Roma and University ofRome, “La Sapienza”, i-00185 Rome, Italy ak Nuclear Physics institute, St. Petersburg, Russia a’ University of California, San Diego, CA 92093, USA am Dept. de Fisica de Particulas Elementales, Univ. de Santiago, E-15706 Santiago de Compostela, Spain an Bulgarian Academy of Sciences, Central Laboratory of Mechatronics and instrumentation, BU-1113 Sofia, Bulgaria a’ Center for High Energy Physics, Korea Advanced inst. of Sciences and Technology 305-701 Taejon, South Korea ap University ofAlabama, Tuscaloosa, AL 35486, USA aq Purdue University, West Lafayette, IN 47907, USA a’ Paul Scherrer institut, PSI, CH-5232 Villigen, Switzerland as DESY-institut fir Hochenergiephysik, D-15738 Zeuthen, FRG af Eidgeniissische Technische Hochschule, ETH Ziirich, CH-8093 Ziirich, Switzerland au Universiv of Hamburg, D-22761 Hamburg, FRG av High Energy Physics Group, Taiwan, ROC
| Funders | Funder number |
|---|---|
| Center for High Energy Physics | |
| Chinese University of Science and Technology | |
| Department of Natural Sciences | |
| I-40126 | |
| INFN Sezione di Firenze | |
| INFN-Sezione | |
| ITEP | |
| Italy aa institute of Theoretical and Experimental Physics | |
| NIKHEF | |
| Tata Institute of Funaknen.tal Research, Bombay | |
| University of Bucharest | |
| University of Lausanne | |
| University of Nymegen | |
| Oak Ridge National Laboratory | |
| Princeton University | |
| Massachusetts Institute of Technology | |
| California Institute of Technology | |
| Boston University | |
| Università degli Studi di Napoli Federico II | |
| Harvard University | |
| University of Michigan | |
| Johns Hopkins University | |
| University of California, San Diego | |
| Carnegie Mellon University | |
| Los Alamos National Laboratory | |
| University of Cyprus | |
| Magyar Tudományos Akadémia | |
| Northeastern University | |
| Bulgarian Academy of Sciences | |
| Université de Genève | |
| University of Science and Technology of China | |
| Università degli Studi di Perugia | |
| Institute of High Energy Physics | |
| i-00185 Rome, Italy ak Nuclear Physics institute |