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 charg inos and neutralinos, with dominant Higgsino components and with masse s within the reach of LEP1.5 (root s = 140 GeV). In this work, we pres ent a detailed analysis of the neutralino and chargino production proc esses for the favoured region of parameter space, that is low values o f \mu\ and either low or large values of tan beta. We find that chargi no 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 ne xt phases of the LEP collider. We also show that, due mainly to phase- space constraints, the lightest neutralinos should be more easily dete ctable than charginos in most of the parameter space preferred by prec ision-measurement data.