Reduction of the Spin-Orbit Splittings at the N=28 Shell Closure

L. Gaudefroy; O. Sorlin; D. Beaumel; Y. Blumenfeld; Z. Dombrádi; S. Fortier; S. Franchoo; M. Gélin; J. Gibelin; S. Grévy; F. Hammache; F. Ibrahim; K. W. Kemper; K.-L. Kratz; S. M. Lukyanov; C. Monrozeau; L. Nalpas; F. Nowacki; A. N. Ostrowski; T. Otsuka; Yu.-E. Penionzhkevich; J. Piekarewicz; E.C. Pollacco; P. Roussel-Chomaz; E. Rich; J. A. Scarpaci; M.G. Saint-Laurent; D. Sohler; M. Stanoiu; T. Suzuki; E. Tryggestad; D. Verney

HAL : in2p3-00090839, version 1

DOI : 10.1103/PhysRevLett.97.092501

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Physical Review Letters 97 (2006) 092501

Reduction of the Spin-Orbit Splittings at the N=28 Shell Closure

L. Gaudefroy^{1, 2}, O. Sorlin^{1, 2}, D. Beaumel¹, Y. Blumenfeld¹, Z. Dombrádi, S. Fortier¹, S. Franchoo¹, M. Gélin², J. Gibelin¹, S. Grévy², F. Hammache¹, F. Ibrahim¹, K. W. Kemper, K.-L. Kratz, S. M. Lukyanov, C. Monrozeau¹, L. Nalpas³, F. Nowacki⁴, A. N. Ostrowski, T. Otsuka, Yu.-E. Penionzhkevich, J. Piekarewicz, E.C. Pollacco³, P. Roussel-Chomaz², E. Rich¹, J. A. Scarpaci¹, M.G. Saint-Laurent², D. Sohler, M. Stanoiu, T. Suzuki, E. Tryggestad¹, D. Verney¹

SPIRAL Collaboration(s)

(2006)

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 p3/2, p1/2, and f5/2 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 ~=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.

1 :	IPNO - Institut de Physique Nucléaire d'Orsay

2 :	GANIL - Grand Accélérateur National d'Ions Lourds

3 :	DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée

4 :	DRS-IPHC - Département Recherches Subatomiques

Thème(s)

Physique/Physique Nucléaire Expérimentale

Mot(s)-clé(s) : 2H-induced transfer reactions – Nuclear spectroscopic factors – Nuclear single-particle levels and strength functions – Properties of nuclei with 39 <= A <= 58


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Contributeur : Michel Lion <>
Soumis le : Lundi 4 Septembre 2006, 09:47:41
Dernière modification le : Lundi 4 Septembre 2006, 13:29:48