New 0 + states in 146Sm from a (p,t) experiment and the particle-core coupling model

Abstract

The reaction 148Sm(p,t) 146Sm was studied at E p = 26 MeV. Fifty-six excited states in the final N = 84 nucleus were observed below E exc = 4.2 MeV and their angular distributions were measured at 8 angles. Spin and parity assignments are made for 37 of them, based on the determination of the transferred angular momentum L. Ten excited J π = 0 + states were identified. The emerging excitation energies of the J π = 0 + states and the monopole strength distribution in 146Sm are compared with those observed in nearby nuclei and with results of calculations done in the framework of the Particle-Core Coupling Model. The main features of the experimental results are interpreted using a superposition of two types of configurations: two-particle states coupled to the collective excitations of the N = 82 core and two holes coupled to the collective excitations of the N = 86 core. Calculations show also that two-phonon⊗two-particle configurations are spread over many states and their identification becomes difficult.