Orbital Dependent Nucleonic Pairing in the Lightest Known Isotopes of Tin
Darby, Iain × Grzywacz, R.K. Batchelder, J.C. Bingham, C.R. Cartegni, L. Gross, C.J. Hjorth-Jensen, M. Joss, D.T. Liddick, S.N. Nazarewicz, W. Padgett, S. Page, R.D. Papenbrock, T. Rajabali, Mustafa Rotureau, J. Rykaczewski, K.P. #
By studying the 109Xe -> 105Te -> 101Sn superallowed alpha-decay chain, we observe low-lying states in
101Sn, the one-neutron system outside doubly magic 100Sn. We find that the spins of the ground state
(J=7/2) and first excited state (J=5/2) in 101Sn are reversed with respect to the traditional level
ordering postulated for 103Sn and the heavier tin isotopes. Through simple arguments and state-of-the-art
shell-model calculations we explain this unexpected switch in terms of a transition from the single-particle
regime to the collective mode in which orbital-dependent pairing correlations dominate.