JYFL-ACCLAB-JM29 In-beam spectroscopy and recoil-beta tagging study of the Tz = -1 nucleus 70Kr

Excited states in the 70Kr and 70Br nuclei were populated via the 40Ca(32S,2n)70Kr and 40Ca(32S,pn)70Br fusion-evaporation reactions at the Accelerator Laboratory of the University of Jyväskylä. The 2+ -> 0+ and 4+ -> 2+ transitions in 70Kr have been found to be 881(1) keV and (tentatively) 1037(2) keV, respectively. Several new gamma-ray transitions were also identified in 70Br, and the T = 1 band has been tentatively extended up to J=10+. The newly observed transitions in 70Kr and 70Br resolve discrepancies in the previously reported results for these nuclei. The experimental Coulomb, triplet, and mirror energy differences are compared with the results of two independent shell-model calculations. The comparisons aim to investigate the shape evolution and the role of the isospin breaking interactions in this mass region.