Higgsinos in SUSY models with gaugino mass unification

In the MSSM, the assumptions of a common sfermion mass parameter mo and a common gaugino mass parameter m(1/2), along with the requirements from radiative electroweak symmetry breaking, lead to relatively large values of the Higgs mixing parameter mu, and consequently to a gaugino-like lightest neutralino <(chi)over tilde>(0)(1). Lifting the requirement that the Higgs mass parameters m(HD) and m(HU) unify with the sfermion masses is known to allow for smaller mu. We show that a mu parameter sufficiently small to yield a Higgsino-like neutralino <(chi)over tilde>(0)(1) requires a precise adjustment of the Higgs mass parameter m(HU). Consequently a gaugino-type neutralino is still preferred in SUSY models with gaugino mass unification. (C) 1999 Published by Elsevier Science B.V. All rights reserved.