High-spin states in ^{127}Ce and ^{129}Ce: Further evidence for triaxial nuclear shapes

High-spin states have been studied in the neutron-deficient odd-N Ce-127 and Ce-129 isotopes, produced in Mo-100(S-32,5n gamma) and Mo-100(S-34,5n gamma) reactions, using the Euroball and Eurogam gamma-ray spectrometers, respectively. A quadruples analysis (gamma(4)) of the coincident gamma-ray data has established new band structures in Ce-127,Ce-129 and extended the known bands to higher spin. In addition, links have been established between two positive-parity bands in Ce-127 allowing a reassignment of I-pi=1/2(+) to the ground state of this nucleus. Configuration assignments are made by comparison of band properties with cranked Woods-Saxon calculations and systematics of other light odd-N cerium isotopes. Unusually large signature splitting in the negative-parity bands is discussed in terms of nonaxial nuclear shapes induced by the core-polarization effects of h(11/2) neutrons.