Probing the nature of particle-core couplings in (49)Ca with gamma spectroscopy and heavy-ion transfer reactions RID G-1784-2011

Neutron rich nuclei around (48)Ca have been measured with the CLARA-PRISMA setup, making use of (48)Ca on (64)Ni binary reactions, at 5.9 MeV/A. Angular distributions of gamma rays give evidence, in several transfer channels, for a large spin alignment (approximate to 70%) perpendicular to the reaction plane, making it possible to firmly establish spin and parities of the excited states. In the case of (49)Ca, states arising from different types of particle-core couplings are, for the first time, unambiguously identified on basis of angular distribution, polarization and lifetime measurements. Shell model and particle-vibration coupling calculations are used to pin down the nature of the states. Evidence is found for the presence, in the same excitation energy region, of two types of coupled states, i.e. single particle coupled to either (48)Ca or (50)Ca simple configurations, and particle-vibration coupled states based on the 3- phonon of (48)Ca. (C) 2011 Elsevier B.V. All rights reserved.