The deformed 0+ state in 34Si

S. Paschalis*, P. Fallon, A. O. Macchiavelli, M. Petri, P. C. Bender, M. P. Carpenter, X. Chen, C. J. Chiara, R. M. Clark, M. Cromaz, S. Gros, L. Hamilton, C. R. Hoffman, R. V F Janssens, T. Lauritsen, I. Y. Lee, C. J. Lister, E. A. McCutchan, L. Phair, W. ReviolD. G. Sarantites, D. Seweryniak, S. L. Tabor, Y. Toh, M. Wiedeking, S. Zhu

*Corresponding author for this work

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The energy of the lowest deformed 2-particle 2-hole (2p2h) 0+ state in even-even N = 20 nuclei is a key observable directly related to the size of the neutron N = 20 shell closure. 34Si, with 14 protons and 20 neutrons, lies at the boundary of the "island of inversion", where the deformed 2p2h 0+ state is the ground state in even-A nuclei. In 34Si, the 2p2h 0+ state is expected to be particularly low lying - in some theories it is even predicted to lie below the first 2 + state. While there have been a number of attempts, using various techniques, no experiment to date has been able to firmly locate the 34Si 2p2h 0+ state although a number of candidates have been suggested. Here we present, for the first time, data obtained from a fusion-evaporation reaction 18O(18O, 2p) to produce 34Si. Gammasphere and Microball were used to detect γ-γ coincidences and charged particles (two protons), respectively. The increased sensitivity of this experiment using γ-γ coincidences and a high charged-particle detection efficiency helped to exclude previously reported candidates and provided a stringent limit on the anticipated γ decay from the first 2+ state to the 2p2h 0+ state.

Original languageEnglish
Article number092050
JournalJournal of Physics: Conference Series
Issue numberSECTION 9
Publication statusPublished - 2011

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