Competing Single-Particle and Collective Behavior in 71Se
Physical Review C
The high-spin decay of 71Se was studied using the 54Fe(23Na,αpn) reaction at 80 MeV and the Florida State University Compton-suppressed Ge array consisting of three clover detectors and seven single-crystal detectors. Based on prompt γ-γ coincidences measured in the experiment, the known level scheme was enhanced and extended to higher spin with 19 new transitions. A band that was previously suggested to have positive parity was reassigned as the “missing” signature partner of an existing negative-parity band. Spins were assigned based on directional correlation of oriented nuclei ratios. Lifetimes of 17 excited states were measured using the Doppler-shift attenuation method. Experimental Qt values imply an intermediate degree of collective behavior for 71Se at high spin. Theoretical Qtvalues determined from cranked Woods-Saxon (CWS) calculations show better agreement with the experimental ones for the positive-parity states than the negative-parity states. Shape competition and γ softness characterize the low-spin states of the lowest positive- and negative-parity bands based on the CWS calculations. At high spin, triaxial shapes with γ>0∘ are predicted.
Haring-Kaye, Robert A.; Howe, Alex; Doering, Joachim; Baker, N. R.; Kuhn, S. J.; Tabor, S.L.; Arora, S.R.; Bruckman, J. K.; and Hoffman, C. R., "Competing Single-Particle and Collective Behavior in 71Se" (2012). Physics & Astronomy Faculty Work. 11.
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