Experimental study of the 2n-transfer reaction Ba-138(O-18,O-16)Ba-140 in the projectile energy range 61-67 MeV [Experimental study of the 2n-transfer reaction 138Ba(18O,16O)140Ba in the projectile energy range 61-67 MeV]

Two-neutron transfer reactions serve as an important tool for nuclear-structure studies in the neutron-rich part of the nuclear chart. In this paper, we report on the first experimental attempt to populate the excited states of140Ba employing the 2n-transfer reaction138Ba(18O,16O)140Ba. 140Ba is highly important, as it is placed on the onset of octupole correlations and the lifetimes of its excited states are completely unknown, with the sole exception of the first 2+ state. The experiment was carried out at the Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH) in Magurele, Romania. Lower limits on the lifetimes of the ground state band up to the 8+ state are reported. Furthermore, relative cross-sections regarding the 2n-transfer reaction with respect to the fusion and the total inelastic reaction channels have been deduced. Further investigation directions of the nuclear structure of 140Ba are also discussed.