Fast-timing lifetime measurements of excited states inCu67

Abstract

The half-lives of the 9/2 + , 13/2 + , and 15/2 + yrast states in the neutron-rich 67 Cu nucleus were determined by using the in-beam fast-timing technique. The experimentally deduced E3 transition strength for the decay of the 9/2 + level to the 3/2 − ground state indicates that the wave function of this level might contain a collective component arising from the coupling of the odd proton p 3/2 with the 3 − state in 66 Ni. Theoretical interpretations of the 9/2 + state are presented within the particle-vibration weak-coupling scheme involving the unpaired proton and the 3 − state from 66 Ni and within shell-model calculations with a 56 Ni core using the jj44b residual interaction. The shell model also accounts reasonably well for the other measured electromagnetic transition probabilities.

Approaching complete low-spin spectroscopy ofBi210with a cold-neutron capture reaction

“…Indeed, within a weak-coupling approach one may expect several states arising from the coupling of the 3 − phonon to the lowest excitations in 210 Bi, i.e., 1 − , 0 − , 9 − , 2 − , and 3 − . This coupling would give a number of positive-parity states characterized by spin values between 2 and 12 and located around 2.6 MeV, although splitting of the order of hundreds of keV or more can be expected [22][23][24][25][26]. The 12 unassigned states, mentioned above, could be of this origin.…”

Study of Low-spin States in Ca Isotopes via Neutron Capture Reactions

“…From the experimental point of view, indications of particle-phonon coupled states have been found mostly in medium-heavy nuclei [1], while scarce information exists for medium-light systems [2][3][4][5] and moving away from the stability valley. In the latter case, particle-phonon coupled states would also provide complementary information on the robustness or softness of the nuclear collectivity far from stability.…”

Particle-core Couplings Close to Neutron-rich Doubly-magic Nuclei

“…Such calculations, for the specific case of 133 Sb, are under development within a microscopic framework using consistently Skyrme ef-fective interactions [22]. This will represent a significant step forward with respect to paticle-phonon calculations, performed, for many decades, by using the phenomenological model of Bohr and Mottelson [1], based on a weak-coupling approach and on purely phenomenological inputs [11][12][13][14].…”

“…The examples include 206−209 Pb, 206,207 Tl and 206 Hg [4,5]. Several indications of states of particle-phonon nature have also been found around other doubly-magic and semi-magic nuclei lying near the stability valley [6][7][8][9][10][11][12][13][14], while searches for particle-phonon coupled states away from the stability valley, as, for example, in neutron-rich nuclei, are expected to provide information on the robustness or softness of nuclear collectivity which can be measured with the purity of single-nucleon excitations on top of core vibrations.…”