Collective 2p-2h intruder states in Sn-118 studied via beta decay of In-118 using the GRIFFIN spectrometer at TRIUMF

The low-lying structure of semimagic Sn-118 has been investigated through the beta decay of In-118 (T-1/2 = 4.45 min) to study shape coexistence via the reduced transition probabilities of states in the 2p-2h proton intruder band. This high-statistics study was carried out at TRIUMF-ISAC with the GRIFFIN spectrometer. In total, 99 transitions have been placed in the level scheme with 43 being newly observed. Three low-lying gamma-ray transitions with energies near 285 keV have been resolved from which the 2(intr.)(+) -> 0(intr.)(+) 284.52-keV transition was determined to have half of the previous branching fraction leading to a B (E2; 2(2)(+)-> 0(2)(+)) of 21(4) W.u. compared to 39(7) W.u. from the previous measurement. Calculations using sd IBM-2 with mixing have also been made to compare the experimental B(E2) values to the theoretical values and to make comparisons to the Sn-114,Sn-116 isotopes previously studied using the same theoretical model.