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

TL;DR

This study explores the use of two-neutron transfer reactions to investigate the excited states and nuclear structure of $^{140}$Ba, providing new lifetime data and cross section measurements in the neutron-rich region.

Contribution

First experimental investigation of $^{140}$Ba excited states using 2n-transfer reactions, offering lifetime limits and cross section data for the first time.

Findings

Lower limits on lifetimes of excited states up to 8+

Relative cross sections for 2n-transfer compared to other channels

Insights into octupole correlations in $^{140}$Ba

Abstract

Two-neutron transfer reactions serve as an important tool for nuclear structure studies in the neutron rich part of the nuclear chart. In this article, we report on the first experimental attempt to populate the excited states of $^{140}$Ba employing the 2n-neutron transfer reaction $^{138}$Ba($^{18}$O,$^{16}$O)$^{140}$Ba. $^{140}$Ba 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 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 $^{140}$Ba are also discussed.