Gaudefroy L, Sorlin O, Beaumel D, Blumenfeld Y, Dombrádi Z, Fortier S, Franchoo S, Gélin M, Gibelin J, Grévy S, Hammache F, Ibrahim F, Kemper KW, Kratz KL, Lukyanov SM, Monrozeau C, Nalpas L, Nowacki F, Ostrowski AN, Otsuka T, Penionzhkevich YE, Piekarewicz J, Pollacco EC, Roussel-Chomaz P, Rich E, Scarpaci JA, St Laurent MG, Sohler D, Stanoiu M, Suzuki T, Tryggestad E, Verney D. Reduction of the spin-orbit splittings at the n = 28 shell closure.
Phys Rev Lett 2006;
97:092501. [PMID:
17026356 DOI:
10.1103/physrevlett.97.092501]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Indexed: 05/12/2023]
Abstract
The N = 28 shell closure has been investigated via the 46Ar(d,p)47Ar transfer reaction in inverse kinematics. Energies and spectroscopic factors of the neutron p(3/2), p(1/2), and f(5/2) states in 47Ar were determined and compared to those of the 49Ca isotone. We deduced a reduction of the N = 28 gap by 330(90) keV and spin-orbit weakenings of approximately 10(2) and 45(10)% for the f and p states, respectively. Such large variations for the f and p spin-orbit splittings could be accounted for by the proton-neutron tensor force and by the density dependence of the spin-orbit interaction, respectively. This contrasts with the picture of the spin-orbit interaction as a surface term only.
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