Evidence for octupole collectivity in  172 Pt

• Published in: The European physical journal. A, Hadrons and nuclei Vol. 56; no. 2
• Main Authors: Ertoprak, Aysegul, Cederwall, Bo, Qi, Chong, Aktas, Özge, Doncel, Maria, Hadinia, Baharak, Liotta, Roberto, Sandzelius, M., Scholey, C., Andgren, Karin, Bäck, Torbjörn, Badran, H., Braunroth, T., Calverley, T., Cox, D. M., Cullen, D. M., Fang, Y. D., Ganioglu, E., Giles, M., Gomez-Hornillos, M.B., Grahn, T., Greenlees, P. T., Hilton, J., Hodge, D., Ideguchi, E., Jakobsson, U., Johnson, Arne, Jones, P.M., Julin, R., Juutinen, S., Ketelhut, S., Khaplanov, Anton, Kumar Raju, M., Leino, M., Li, H., Liu, H., Matta, Sanya, Modamio, V., Nara Singh, B. S., Niikura, M., Nyman, M., Özgur, I., Page, R. D., Pakarinen, J., Papadakis, P., Partanen, J., Paul, E. S., Petrache, C. M., Peura, P., Rahkila, P., Ruotsalainen, P., Saren, J., Sorri, J., Stolze, S., Subramaniam, Pranav, Taylor, M. J., Uusitalo, J., Valiente-Dobon, J. J., Wyss, Ramon Alexander
• Format: Journal Article
• Language: English
• Published: 2020
• ISSN: 1434-6001; 1434-601X
• DOI: 10.1140/epja/s10050-020-00071-6

Excited states in the extremely neutron-deficient nucleus 172 Pt were populated via 96 Ru( 78 Kr,2p) and 92 Mo( 83 Kr,3n) reactions. The level scheme has been extended up to an excitation energy of  ~ 5 MeV and tentative spin-parity assignments up to I π  = 18 + . Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negative-parity band. The lowest member of this negative-parity structure was firmly assigned spin-parity 3 - . In addition, we observed an E3 transition from this 3 -  state to the ground state, providing direct evidence for octupole collectivity in 172 Pt. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the 3 - state as a collective octupole-vibrational state.