Lifetime measurements of the high spin yrast states in 128Ce

Lifetime measurements of the high spin states in the yrast band of ¹²⁸Ce were performed using the Doppler shift attenuation method in connection with the reaction ¹⁰⁰Ru(³²S, 2p2n) ¹²⁸Ce at incident energy of 141 MeV. In the vicinity of the band crossing, the previously reported anomalously high B(E2) value was not observed. The gross behavior of the normalized transition strength is approximate to symmetric rotor. It is confirmed that the trend of increase in collectivity with decreasing neutron number, which was indicated in the previous studies on ^{130, 132, 134}Ce, continues in ¹²⁸Ce. The value of quadrupole deformation parameter β₂ deduced from the measured lifetimes is in good agreement with the theoretical calculation using a cranking model based on a non-axially deformed Woods-Saxon potential.