OBSERVATION OF THE I-SOFT NUCLEUS BA-134( SCISSORS MODE IN THE GAMMA)

A photon scattering experiment was performed on the gamma-soft nucleus Ba-134 with photon energies of E(gamma)<4.1. Around 3 MeV excitation energy a fragmented 1(+) scissors mode as well as the (2(+) x 3(-))(1- ) two-phonon dipole state were identified. The dipole excitation stren gths were measured. The excitation strength of the scissors mode in th is gamma-soft nucleus is well reproduced by an empirical M1 sum rule t hat generalizes the ''delta(2) law'' to nuclei without axial symmetry. The IBM-2 describes the mixed-symmetry slates in Ba-134 and their dec ay pattern. A large E2/M1 mixing ratio for the 1(+) --> 2(1)(+) decay of the scissors mode to the 2(1)(+) state is predicted by the IBM-2. T he new result from Ba-134 together with a similar previous observation in Pt-196 corroborates the scissors made as a typical excitation mode of gamma-soft nuclei.