  In the CP-violating Minimal Supersymmetric Standard Model, we study the pair
production of neutralinos at center-of-mass energies around the heavy neutral
Higgs boson resonances. For longitudinally polarized muon beams, we analyze CP
asymmetries which are sensitive to the interference of the two heavy neutral
Higgs bosons. Due to radiatively induced scalar-pseudoscalar transitions, the
CP asymmetries can be strongly enhanced when the resonances are nearly
degenerate, as in the Higgs decoupling limit. The Higgs couplings to the
neutralino sector can then be analyzed in the presence of CP violating phases.
We present a detailed numerical analysis of the cross sections, neutralino
branching ratios, and the CP observables. We find that radiatively induced CP
violation in the Higgs sector leads to sizable CP-asymmetries, which are
accessible in future measurements at a muon collider. However, we expect that
our proposed method should be applicable to other processes with nearly
degenerate scalar resonances, even at hadron colliders.
