Low-lying states in Mg32 studied by proton inelastic scattering

Proton inelastic scattering on the neutron-rich nucleus Mg-32 has been studied at 46.5 MeV/nucleon in inverse kinematics. Populated states were identified by measuring de-excitation gamma rays, in which five new states were found by gamma-gamma coincidence analyses. By analyzing the angular differential cross sections via coupled-channel calculations, their spins and parities were constrained and the amplitudes for each transition were extracted. The spin and parity of the 2321-keV state was assigned as 4(1)(+). The ratio between the energies of the 2(1)(+) and 4(1)(+) states indicates that Mg-32 is a transitional nucleus rather than an axially deformed rigid rotor. The collectivities in the nucleus Mg-32 with N=20 are discussed based on the results obtained in the present experiment.