Résumé du preprint Irfu-10-44
| Irfu-10-44 |
|---|
| Migration of nuclear shell gaps studied in the d(Ne,p gamma)Ne reaction |
| W.N. Catford, C.N. Timis, R.C. Lemmon, M. Labiche, N.A. Orr, B. Fernandez-Dominguez, R. Chapman, M. Freer, M. Chartier, H. Savajols, M. Rejmund, N.L. Achouri, N. Amzal, N.I. Ashwood, T.D. Baldwin, M. Burns, L. Caballero, J.M. Casadjian, N. Curtis, G. de France, W. Gelletly, X. Liang, S.D. Pain, V.P.E. Pucknell, B. Rubio, O. Sorlin, K. Spohr, Ch. Theisen and D.D. Warner |
| The transfer of neutrons onto 24Ne has been measured using a reaccelerated radioactive beam of 24Ne to study the (d,p) reaction in inverse kinematics. The unusual raising of the first 3/2+ level in 25Ne and its significance in terms of the migration of the neutron magic number from N=20 to N=16 is put on a firm footing by confirmation of this state’s identity. The raised 3/2+ level is observed simultaneously with the intruder negative parity 7/2- and 3/2- levels, providing evidence for the reduction in the N=20 gap. The coincident gamma-ray decays allowed the assignment of spins as well as the transferred orbital angular momentum. The excitation energy of the 3/2+ state shows that the established USD shell model breaks down well within the sd model space and requires a revised treatment of the proton-neutron monopole interaction. |