Phenomenology of ``inos'' in the Light Gaugino Scenario and Possible Evidence for a $\sim 53$ GeV Chargino

Abstract

The tree-level-massless gaugino scenario predicts that the lighter chargino mass is less than m_W and that gluino and lightest neutralino masses are $\text{lsi}1$ GeV. In this case the dominant decay mode of charginos and non-LSP neutralinos is generically to three jets. The excess of "4j" events with total invariant mass $\sim 105$ GeV observed in LEP running at 130-136 GeV is noted to be consistent with pair production of $\sim 53$ GeV charginos. Data at 161 and 172 GeV from Fall, 1996, cannot conclusively test this hypothesis (because cuts to eliminate $W^{+}{W}^{-}$ background reduce the efficiency significantly) but is suggestive that the signal persists.

Comments: Invited talk at ICHEP96, Warsaw, July, 1996. Based on contributed paper pa11-048 and RU-96-71 (hep-ph/9608387)