2020 Impact factor 3.043
Hadrons and Nuclei
Eur. Phys. J. A 15, 157-160 (2002)
DOI: 10.1140/epja/i2001-10245-5

Shape coexistence and the $\mth{N=20}$ shell closure far from stability by inelastic scattering

W. Mittig1, H. Savajols1, D. Baiborodin1, 2, J.M. Casandjian1, C.E. Demonchy1, P. Roussel-Chomaz1, F. Sarazin1, Z. Dlouhý2, J. Mrazek2, A.V. Belozyorov3, S.M. Lukyanov3, Y.E. Penionzhkevich3, N. Alamanos4, A. Drouart4, A. Gillibert4, C. Jouanne4, V. Lapoux4, E. Pollacco4, A. Korichi5 and J.A. Scarpaci6

1  GANIL (DSM/CEA, IN2P3/CNRS), BP 5027, 14076 Caen Cedex 5, France
2  Nuclear Physics Institute, ASCR, 25068 Rez, Czech Republic
3  FLNR, JINR, Dubna, P.O. Box 79, 101 000 Moscow, Russia
4  CEA/DSM/DAPNIA/SPhN, Saclay, 91191 Gif-sur-Yvette Cedex, France
5  CSNSM, F-91405 Campus Orsay, France
6  IPN, F-91406 Orsay Cedex, France

mittig@ganil.fr

(Received: 21 March 2002 / Published online: 31 October 2002)

Abstract
Following mass measurements in the region N=20 and N=28, we have studied inelastic nuclear scattering for the nuclei 34Si, 33Al and 32Mg. No evidence for a low-lying shape isomeric 0 + state was found in 34Si, and an upper limit for the population cross-section could be established, rendering its existence very unlikely. A new transition was found in 33Al, that is a good candidate for a 2p-2h state and therefore a determination of the 2p-2h gap at N=20. Inelastic nuclear scattering strongly excites 3 - states, as seen in 34Si. A strong transition was found in 32Mg that should correspond to the first 3 - in this nucleus, lying very low as compared to theory and systematics in this region.

PACS
21.10.Re - Collective levels.
25.60.-t - Reactions induced by unstable nuclei.

© Società Italiana di Fisica, Springer-Verlag 2002