Light Higgsino detection at LEP1.5

Within the minimal supersymmetric extension of the Standard Model, the best fit to the most recent precision-measurement data requires charginos and neutralinos, with dominant Higgsino components and with masses within the reach of LEP1.5 (root s = 140 GeV). In this work, we present a detailed analysis of the neutralino and chargino production processes for the favoured region of parameter space, that is low values of \mu\ and either low or large values of tan beta. We find that chargino and neutralino searches can cover the Higgsino region in the (mu, M(2)) plane for values of M(2) less than or similar to 1 TeV, at the next phases of the LEP collider. We also show that, due mainly to phase-space constraints, the lightest neutralinos should be more easily detectable than charginos in most of the parameter space preferred by precision-measurement data.