Nonsupersymmetric interpretation of the e⁺e^-γγ + missing energy event observed by the Collider Detector at Fermilab

Abstract

The e⁺e^-γγ + E_T event reported recently by the CDF Collaboration has been interpreted as a signal of supersymmetry in several recent papers. In this Rapid Communication, we report on an alternative nonsupersymmetric interpretation of the event using an extension of the standard model that contains new physics at the electroweak scale that does not effect the existing precision electroweak data. We extend the standard model by including an extra sequential generation of fermions, heavy right-handed neutrinos for all generations, and an extra singly charged SU(2)-singlet Higgs boson. We discuss possible ways to discriminate this from the standard supersymemtric interpretations.