Evolution of the nuclear spin-orbit splitting explored via the 32Si(d,p)33Si reaction using SOLARIS

• Published in: Physics letters. B 2024-06, Vol.853, p.138678, Article 138678
• Main Authors: Chen, J., Kay, B.P., Hoffman, C.R., Tang, T.L., Tolstukhin, I.A., Bazin, D., Lubna, R.S., Ayyad, Y., Beceiro-Novo, S., Coombes, B.J., Freeman, S.J., Gaffney, L.P., Garg, R., Jayatissa, H., Kuchera, A.N., MacGregor, P., Mitchell, A.J., Mittig, W., Monteagudo, B., Munoz-Ramos, A., Müller-Gatermann, C., Recchia, F., Rijal, N., Santamaria, C., Serikow, M.Z., Sharp, D.K., Smith, J., Stecenko, J.K., Wilson, G.L., Wuosmaa, A.H., Yuan, C.X., Zamora, J.C., Zhang, Y.N.
• Format: Article
• Language: English
• Subjects: Shell model; Single-particle energies; Spin-orbital splitting; Transfer reaction
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2024.138678

The spin-orbit splitting between neutron 1p orbitals at 33Si has been deduced using the single-neutron-adding (d,p) reaction in inverse kinematics with a beam of 32Si, a long-lived radioisotope. Reaction products were analyzed by the newly implemented SOLARIS spectrometer at the reaccelerated-beam facility at the National Superconducting Cyclotron Laboratory. The measurements show reasonable agreement with shell-model calculations that incorporate modern cross-shell interactions, but they contradict the prediction of proton density depletion based on relativistic mean-field theory. The evolution of the neutron 1p-shell orbitals is systematically studied using the present and existing data in the isotonic chains of N=17, 19, and 21. In each case, a smooth decrease in the separation of the 1p3/2-1p1/2 orbitals is seen as the respective p-orbitals approach zero binding, suggesting that the finite nuclear potential strongly influences the evolution of nuclear structure in this region.