Low energy supersymmetry with a neutralino LSP and the CDF eeγγ + / E T event

We present a refined and expanded analysis of the CDF eeγγ+ / ET event as superpartner production, assuming the lightest neutralino is the lightest supersymmetric particle. A general low-energy Lagrangian is constrained by a minimum cross section times branching ratio into two electrons and two photons, kinematics consistent with the event, and LEP1LEP130 data. We examine how the supersymmetric parameters depend on the kinematics, branching ratios and experimental predictions with a selectron interpretation of the event, and discuss to what extent these are modified by other interpretations. Predictions for imminent CERN LEP upgrades and the present and future Fermilab Tevatron are presented. Finally, we briefly discuss the possible connection to other phenomena including a light stop, the neutralino relic density, the shift in Rb and the associated shift in αs, and implications for the form of the theory. ∗Supported mainly by a INFN postdoctoral fellowship, Italy. 1 [email protected] 2 [email protected] [email protected] 4 [email protected] 5 [email protected]