  We evaluate semi-inclusive neutral-current quasielastic differential neutrino
and antineutrino cross sections within the framework of the relativistic
impulse approximation. The results of the relativistic mean field and of the
relativistic Green's function models are compared. The sensitivity to the
strange-quark content of the nucleon form factor is also discussed. The results
of the models are compared with the MiniBooNE experimental data for neutrino
scattering. Numerical predictions for flux-averaged antineutrino scattering
cross sections are also presented.
