Mirror Nuclei - Isospin Symmetry Breaking in the Mass A=35 and A=51 Mirror Nuclei

Abstract: High-spin states in the A=35 mirror nuclei 35Ar and 35Cl and A=51 mirror nuclei 51Fe and 51Mn were populated using fusion-evaporation reactions. The gamma rays were detected in the powerful Ge arrays Gammasphere and GASP, respectively, which operated in conjunction with ancillary detectors for evaporated particles. The resulting mirror energy difference diagrams of the two mirror pairs are interpreted in terms of various electromagnetic effects and possible isospin-symmetry breaking components of the nuclear force. In the A=35 mirror nuclei effects of the electromagnetic spin-orbit interaction have been discriminated for the first time. In addition, an unusual decay pattern of excited states can give direct evidence on isospin mixing. Excited states in 51Fe have been observed for the first time. In the A=51 mirror nuclei detailed isospin-symmetry studies are performed including core-excited states. This mark the first comparison of such analogue states in mirror nuclei. An extensive level scheme of the nucleus 51Mn has been constructed. It comprises approximately 50 previously unknown core excited states, which are interpreted in terms of comprehensive large shell-model calculations including electro-magnetic decay properties. In addition, a rotational band has been identified, which is interpreted using the cranked Nilsson-Strutinsky model and found to comprise a particle in the 1g9/2 intruder orbital.