Collective excitations in 150Gd

AbstraktAbstract

Mean lifetime measurements of low-lying yrast positive-and negative-parity states of 150Gd have been performed with the ROSPHERE array using the 140Ce(13C,3n) fusion-evaporation reaction and the recoil distance Doppler shift method. Precise branching ratios have been obtained from a complementary electron capture decay experiment of both the isomer and ground state of 150Tb.Reduced E1, E2, and E3 transition probabilities were extracted and compared with the corresponding observables in the neighboring isotopes and isotones. The experimental data are compared to the predictions of various theoretical models: quasiparticle random phase approximation, time-dependent Hartree-Fock calculations, the quadrupole-octupole collective Hamiltonian, the mean-field mapped interacting boson model, and the triaxial projected shell model. We find that a complete description of both quadrupole and octupole collectivity, from ground and excited states, is currently lacking, and such measurements of transition strengths are crucial for constraining present and future calculations.

Mean lifetime measurements of low-lying yrast positive-and negative-parity states of 150Gd have been performed with the ROSPHERE array using the 140Ce(13C,3n) fusion-evaporation reaction and the recoil distance Doppler shift method. Precise branching ratios have been obtained from a complementary electron capture decay experiment of both the isomer and ground state of 150Tb.Reduced E1, E2, and E3 transition probabilities were extracted and compared with the corresponding observables in the neighboring isotopes and isotones. The experimental data are compared to the predictions of various theoretical models: quasiparticle random phase approximation, time-dependent Hartree-Fock calculations, the quadrupole-octupole collective Hamiltonian, the mean-field mapped interacting boson model, and the triaxial projected shell model. We find that a complete description of both quadrupole and octupole collectivity, from ground and excited states, is currently lacking, and such measurements of transition strengths are crucial for constraining present and future calculations.