부산대학교 도서관

Recent data resulting from studies of two-nucleon transfer reaction on [sup.11]Li, analyzed through a unified nuclear-structure-direct-reaction theory have provided strong direct as well as indirect confirmation, through the population of the first excited state of [sup.9]Li and of the observation of a strongly quenched ground state transition, of the prediction that phonon-mediated pairing interaction is the main mechanism binding the neutron halo of the 8.5-ms-lived [sup.11]Li nucleus. In other words, the ground state of [sup.11]Li can be viewed as a neutron Cooper pair bound to the [sup.9]Li core, mainly through the exchange of collective vibration of the core and of the pigmy resonance arizing from the sloshing back and forth of the neutron halo against the protons of the core, the mean field leading to unbound two-particle states, a situation essentially not altered by the bare nucleon--nucleon interaction acting between the halo neutrons. Twoneutron pick-up data, together with (t,p) data on [sup.7]Li, suggest the existence of a pairing vibrational band based on [sup.9]Li, whose members can be excited with the help of inverse kinematic experiments as was done in the case of [sup.11]Li[(p, t)sup.9]Li reaction. The deviation from harmonicity can provide insight into the workings of medium polarization effects on Cooper-pair nuclear pairing, let alone specific information concering the 'rigidity' of the N = 6 shell closure. Further information concerning these questions is provided by the predicted absolute differential cross sections [σ.sub.abs] associated with the reactions [sup.12]Be(p, t)[.sup.10]Be(g.s.) and [sup.12]BE [(p, t).sup.10] Be(pv) (≅ [sup.10]Be[(p, t).sup.8] Be(g.s.)). In particular, concerning this last reaction, predictions of [σ.sub.abs] can change by an order of magnitude depending on whether the halo properties associated with the [d.sub.5/2] orbital are treated selfconsistently in calculating the ground state correlations of the (pair removal) mode, or not. DOI: 10.1134/S106377881407014X
1. DEDICATION In his contribution to a just published volume with the title Fifty Years of Nuclear BCS (World Sci., Singapore, 2013, p. 3) Professor Spartak Belyaev recounts some aspects [...]