  Binding energies and widths of three-body KbarNN, and of four-body KbarNNN
and KbarKbarNN nuclear quasibound states are calculated in the hyperspherical
basis, using realistic NN potentials and subthreshold energy dependent chiral
KbarN interactions. Results of previous K^-pp calculations are reproduced and
an upper bound is placed on the binding energy of a K^-d quasibound state. A
self consistent handling of energy dependence is found to restrain binding,
keeping the calculated four-body ground-state binding energies to relatively
low values of about 30 MeV. The lightest strangeness -2 particle-stable Kbar
nuclear cluster is most probably KbarKbarNN. The calculated Kbar N -> pi Y
conversion widths range from approximately 30 MeV for the KbarNNN ground state
to approximately 80 MeV for the KbarKbarNN ground state.
