Abstract
We report on the -factor measurement of the first isomeric state in [, , and ]. The spin-parity of the isomer and the intruder nature of the ground state of the nucleus are experimentally established for the first time, providing direct and unambiguous evidence of the collapse of the shell closure in neutron-rich nuclei. The shell model, beyond the mean-field and semiempirical calculations, provides a very consistent description of this nucleus showing that a well deformed prolate and quasispherical states coexist at low energy.
- Received 30 October 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.092501
©2009 American Physical Society
Viewpoint
Peaceful coexistence of nuclear shapes
Published 2 March 2009
Experiments show that spherical and nonspherical states of a light nucleus near neutron number 28 coexist at the same energy, challenging the usefulness of the notion of stable and persistent “magic numbers.”
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