Search for neutron excitations across the N=20 shell gap in $^{25-29}$Ne

M. Belleguic (1) , F. Azaiez (1) , Zs. Dombrádi , D. Sohler , M.J. Lopez-Jimenez (2) , T. Otsuka , M.G. Saint-Laurent (2) , O. Sorlin (1) , M. Stanoiu (1, 2) , Y. Utsuno , Yu.-E. Penionzhkevich , N.L. Achouri (3) , J.C. Angélique (3) , C. Borcea , C. Bourgeois (1) , J.M. Daugas (2) , Francois de Oliveira Santos (2) , Z. Dlouhy , C. Donzaud (1) , J. Duprat (1) , Z. Elekes , S. Grévy (3) , D. Guillemaud-Mueller (1) , S. Leenhardt (1) , M. Lewitowicz (2) , S. M. Lukyanov , W. Mittig (2) , M. G. Porquet (4) , F. Pougheon (1) , P. Roussel-Chomaz (2) , H. Savajols (2) , Y. Sobolev , C. Stodel (2) , J. Timár

1 IPNO - Institut de Physique Nucléaire d'Orsay
2 GANIL - Grand Accélérateur National d'Ions Lourds
3 LPCC - Laboratoire de physique corpusculaire de Caen
4 CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse

Nuclear structure of the neutron rich $^{25-29}$Ne nuclei has been investigated through the in-beam $\gamma$-ray spectroscopy technique using fragmentation reactions of both stable and radioactive beams. Level schemes have been deduced for these Ne isotopes. In order to examine the importance of intruder $fp$ configurations, they are compared to shell model calculations performed either in the restricted sd or in the larger $sdpf$ valence space. The $^{25,26}$Ne and ${27}$Ne nuclei were found to be in agreement with the $sd$ shell model calculations, whereas $^{28}$Ne exhibits signatures of the intruder $fp$ shell contribution.

Mots clés: nuclear energy level transitions; nuclear shell model; nuclei with mass number 20 to 38; gamma-ray spectra; nuclear energy levels; nuclear fragmentation

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

M. Belleguic, F. Azaiez, Zs. Dombrádi, D. Sohler, M.J. Lopez-Jimenez, et al.. Search for neutron excitations across the N=20 shell gap in $^{25-29}$Ne. Physical Review C, 2005, 72, pp.054316. ⟨10.1103/PhysRevC.72.054316⟩. ⟨in2p3-00025120⟩