Upper bound on the mass of the lightest neutralino in a general supersymmetric theory with grand unification

Abstract

We derive an upper bound on the mass of the lightest neutralino in a supersymmetric theory containing an arbitrary number of singlet, doublet, and triplet Higgs superfields under the standard model gauge group. Assuming grand unification of the gauge couplings, whereby the theory reduces to the minimal supersymmetric standard model with an arbitrary number of singlets, the bound can be expressed in terms of the gluino mass. Including radiative corrections, the upper bound on the mass of the lightest neutralino is 62 GeV for a gluino mass of 200 GeV, which increases to 178 GeV for a 1 TeV gluino.