New results on excited states in the one-particle one-hole nucleus 56Co measured with Miniball detectors

by Dr Ana Montaner (INFN di Padova)

Friday 9 Nov 2018, 11:00 → 12:30 Europe/Rome

C. VILLI meeting room (INFN-LNL)

In this work we have studied the fusion-evaporation 56Fe(p,n)56Co reaction with an incident proton-beam of 10 MeV. The gamma radiation emitted in the de-excitation of the excited odd-odd 56Co nucleus was measured in-beam with four high-purity germanium (Ge) MINIBALL-triple detectors. The experiment was performed at the Maier-Leibnitz-Laboratory (MLL) of the Technische Universität München (TUM, Germany). This work was partly motivated by a 56Zn-decay experiment performed at GANIL (Caen, France) which populated the excited states in 56Cu, the mirror nucleus of 56Co.
Gamma-gamma coincidences were analysed and a new level scheme of 56Co was constructed. The angular distributions of the gamma-rays were also analysed and allowed us to assign spin-parity values to most of the excited states in the nucleus. The experimental results were compared with large-scale shell-model calculations with the ANTOINE and NuShellX@MSU codes, using the KB3G and GXPF1a effective interactions in a truncated fp-shell valence space.
On the other hand, the study of the isospin mixing between two 0+ states in 56Co (the IAS of 56Feg.s. and a nearby state) was one of the main motivations of this work. The determination of the M1 transition intensities from both states offered new and relevant information about the effects associated to the relative phases of the isospin-mixed states and showed that these two states decay in a different way.