Eur. Phys. J. A 14, 29-36 (2002)
DOI: 10.1140/epja/iepja1393

On the difference between proton and neutron spin-orbit splittings in nuclei

V.I. Isakov¹, K.I. Erokhina², H. Mach³, M. Sanchez-Vega³ and B. Fogelberg<sup>3

1</sup>  Petersburg Nuclear Physics Institute, Russian Academy of Sciences, Gatchina 188300, Russia
²  Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg 194021, Russia
³  Department of Radiation Sciences, Uppsala University, Nyköping S-61162, Sweden

visakov@thd.pnpi.spb.ru

(Received: 13 February 2002 Communicated by V.V. Anisovich)

Abstract
The latest experimental data on nuclei at ¹³²Sn permit us for the first time to determine the spin-orbit splittings of neutrons and protons in identical orbits in this neutron-rich doubly magic region and compare the case to that of ²⁰⁸Pb. Using the new results, which are now consistent for the two neutron-rich doubly magic regions, a theoretical analysis defines the isotopic dependence of the mean-field spin-orbit potential and leads to a simple explicit expression for the difference between the spin-orbit splittings of neutrons and protons. The isotopic dependence is explained in the framework of different theoretical approaches.

PACS
21.60.Cs - Shell model.
21.10.Pc - Single-particle levels and strength functions.
21.60.Jz - Hartree-Fock and random-phase approximations.
24.10.Jv - Relativistic models.

© Società Italiana di Fisica, Springer-Verlag 2002