Evidence for octupole correlations in 124Ba, 125Ba

The gamma decay of the nuclei 124,125Ba has been investigated by means of the EUROBALL spectrometer, coupled to the DIAMANT array of charged-particle detectors, using the reaction 64Ni + 64Ni at E_{beam}=255 and 261 MeV. In the nucleus 125Ba six new E1 transitions have been found to link opposite-parity bands currently interpreted as \nu d_{5/2(+g_{7/2},nu h_11/2}structures. The previously unknown Jpi=3- level in the nucleus $^{124}$Ba has also been identified; its excitation energy is accurately reproduced by a microscopic calculation including octupole correlations. Both issues are bolstered by sizable B(E1)/B(E2) ratios

Octupole signatures in 124,125Ba

The gamma decay of the nuclei 124,125Ba has been investigated with the EUROBALL array, using the reaction 64Ni+64 Ni at E_{beam} = 255 and 261 MeV. Six new E1 transitions have been found in the nucleus 125Ba, suggesting a significant role of octupole correlations in the origin of its parity doublets. The pi = 3-level of the nucleus 124Ba has been identified for the first time. Its excitation energy is in very good agreement with a prediction based on a microscopic model including octupole interactions