Spectroscopy of 70Kr and isospin symmetry in the T = 1 f pg shell nuclei

M M Debenham (1) , M M Bentley (1) , J J Davies (1) , H Haylett (1) , G G Jenkins (1) , P. Joshi (1) , L F Sinclair (1) , R Wadsworth (1) , P Ruotsalainen (2) , J. Henderson (1) , K Kaneko (3) , K. Auranen (2) , H Badran (2) , T. Grahn (2) , P. Greenlees (2) , A. Herzaáň (2) , U. Jakobsson (2) , J J Konki (2) , R. Julin (2) , S. Juutinen (2) , M M Leino (2) , J J Sorri (2) , J J Pakarinen (2) , P Papadakis (2) , P Peura (2) , J J Partanen (2) , P Rahkila (2) , M M Sandzelius (2) , J J Sarén (2) , C. Scholey (2) , S Stolze (2) , J J Uusitalo (2) , H.M. David (4) , G G de Angelis (5) , W. Korten (6) , G G Lotay (7) , M M Mallaburn (8) , Evren Sahin (9)

1 University of York [York, UK]
2 JYU - Department of Physics [Jyväskylä Univ]
3 Department of Physics, Kyushu Sangyo University
4 ANL - Argonne National Laboratory [Lemont]
5 INFN Laboratori Nazionali di Legnaro
6 DPHN - Département de Physique Nucléaire (ex SPhN)
7 UNIS - University of Surrey
8 School of Physics and Astronomy [Manchester]
9 Department of Physics [Oslo]

The recoil-β tagging technique has been used in conjunction with the 40 Ca(32 S ,2n) reaction at a beam energy of 88 MeV to identify transitions associated with the decay of the 2 + and, tentatively, 4 + states in the nucleus 70 Kr. These data are used, along with previously published data, to examine the triplet energy differences (TED) for the mass 70 isobars. The experimental TED values are compared with shell model calculations, performed with the JUN45 interaction in the fpg model space, that include a J = 0 isospin nonconserving (INC) interaction with an isotensor strength of 100 keV. The agreement is found to be very good up to spin 4 and supports the expectation for analog states that all three nuclei have the same oblate shape at low-spin. The A = 70 results are compared with the experimental and shell model predicted TED and mirror energy differences (MED) for the mass 66 and 74 systems. The comparisons clearly demonstrate the importance of the isotensor INC interaction in replicating the TED data in this region. Issues related to the observed MED values and their interpretation within the shell model are discussed.

Domains: Nuclear Experiment [nucl-ex]

M M Debenham, M M Bentley, J J Davies, H Haylett, G G Jenkins, et al.. Spectroscopy of 70Kr and isospin symmetry in the T = 1 f pg shell nuclei. Physical Review C, 2016, 94, pp.54311. ⟨10.1103/PhysRevC.94.054311⟩. ⟨cea-01481486⟩