Search for Chargino-Neutralino Associated Production at the Fermilab Tevatron Collider

Abstract

We have searched in $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$ for events with three charged leptons and missing transverse energy. In the minimal supersymmetric standard model, we expect trilepton events from chargino-neutralino $({\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{\ifmmode\pm\else\textpm\fi{}}{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{2}^{0})$ pair production, with subsequent decay into leptons. We observe no candidate ${e}^{+}{e}^{\ensuremath{-}}{e}^{\ifmmode\pm\else\textpm\fi{}}$, ${e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\mu}}^{\ifmmode\pm\else\textpm\fi{}}$, ${e}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, or ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}{\ensuremath{\mu}}^{\ifmmode\pm\else\textpm\fi{}}$ events in $106{\mathrm{pb}}^{\ensuremath{-}1}$ integrated luminosity. We present limits on the sum of the branching ratios times cross section for the four channels: ${\ensuremath{\sigma}}_{{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{\ifmmode\pm\else\textpm\fi{}}{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{2}^{0}}B({\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{\ifmmode\pm\else\textpm\fi{}}{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{2}^{0}\ensuremath{\rightarrow}3\ensuremath{\ell}+X)<0.34\mathrm{pb}$, ${M}_{{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{\ifmmode\pm\else\textpm\fi{}}}>81.5\mathrm{GeV}{/c}^{2}$, and ${M}_{{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{2}^{0}}>82.2\phantom{\rule{0ex}{0ex}}\mathrm{GeV}{/c}^{2}$ for $\mathrm{tan}\ensuremath{\beta}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2$, $\ensuremath{\mu}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}600\phantom{\rule{0ex}{0ex}}\mathrm{GeV}{/c}^{2}$, and ${M}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{q}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}M}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{g}}$.