Few-Body Syst (2018) 59:11
R. Crespo · E. Cravo
Critical Phenomena: Coexistence of Valence Single
Particle- and Core- Excitations in the
Be Halo Nucleus
Received: 15 December 2017 / Accepted: 17 January 2018 / Published online: 7 February 2018
© Springer-Verlag GmbH Austria, part of Springer Nature 2018
Abstract Neutron knockout from
Be due to the collision with a proton target is evaluated at 300 MeV/u
using the three-body Faddeev/Alt-Grassberger-Sandhas (Faddeev/AGS) equations. The results for the Quasi-
Free-Scattering reaction mechanism are discussed.
At the nuclear landscape, isotopes of p-shell nuclei are particular interesting Quantum Systems. In this region
of the nuclear chart, nuclei with critical thresholds near the ground state for particle/cluster emission due to
strong correlations between the nucleons have been found. For these cases, the longstanding and successful
pillar of Nuclear Physics, the Shell Model mean ﬁeld approach to structure is no longer valid and the couplings
with the open channels need to be taken into account explicitly. An important example,
C, has a strong
cluster correlated structure in second 0
just above threshold for the α decay (the Hoyle state) ; another
Li, has a 2.47 MeV threshold for the α + t emission; ﬁnally an interesting case in the neutron rich
nuclear landscape is the one-neutron Halo nucleus
Be, a foremost example of the breaking of the shell-
model approach. A consistent treatment of these critical phenomena in p-shell nuclei is a key milestone for
experimental, reaction and structure studies.
On the other hand, a variety of ab initio structure approaches can currently describe many properties of the
p shell nuclei. A signiﬁcant progress was made in the understanding of bound state properties for nuclei with
mass number A less than 12 from the fundamental inter-nucleon NN and three-nucleon NNN interactions [2,3].
Recently, a novel ab initio approach was developed capable of treating simultaneously bound and scattering
states of light nuclei, starting with realistic two- and three- nucleon forces . This formalism was applied
swimmingly for the study of n−
He scattering, and capable of describing the parity
Be ground state .
The merging of ab initio structure into reaction approaches taking into account all open channels in equal
footing is mandatory for the interpretation of the data obtained from the future experiments at the Radioactive
This article belongs to the Topical Collection “Critical Stability of Quantum Few-Body Systems”.
R. Crespo (
Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
Centro de Ciências e Tecnologias Nucleares, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela, Portugal
Departamento de Física, Faculdade de Ciências, Centro de Física Nuclear, Universidade de Lisboa, Edifício C8, Campo Grande,
1749-016 Lisboa, Portugal