Manifestation Of The Divergence Between Antisymmetrized-Molecular-Dynamics And Container Pictures Of Be-9 Via Be-9(P, Pn)Be-8 Knockout Reaction

We propose a new approach to probe the spatial extension of the valence neutron orbital in the Be-9 nucleus via the Be-9(p, pn)Be-8 knockout reaction. This property of the nuclear molecular orbital has not been established in previous experimental studies and divergence exists between the theoretical descriptions of Be-9 from different perspectives, i.e., the antisymmetrized molecular dynamics and the container pictures of cluster dynamics. These pictures are represented by two different well-proven microscopic models, the antisymmetrized molecular dynamics (AMD) and Tohsaki-Horiuchi-Schuck-Ropke (THSR) wave functions. The corresponding reduced width amplitudes (RWAs) in the Be-8+n channel are extracted from both the AMD and THSR wave functions, and they are found to describe drastically different valence-nucleon motion, which shows the theoretical ambiguity in describing the pi-orbitals in Be-9. Using the RWAs as input, the physical observables of the Be-9(p, pn)Be-8 knockout reaction are predicted by the distorted-wave impulse approximation (DWIA) framework. The magnitudes of the triple differential cross sections (TDX) are found to be highly sensitive to the RWA input. It is concluded that the Be-9(p, pn)Be-8 knockout reaction could provide a feasible probing for the subtle differences between several structure models manifesting through the spatial extension of the pi-orbital in the Be-9 nucleus. (C) 2021 Published by Elsevier B.V.