The effects of core excitation in the breakup of exotic nuclei

Abstract

Breakup of exotic nuclei is discussed within the context of the recently developed XCDCC (eXtended Continuum Discretized Coupled Channel) model. The method is applied to the breakup of 11 Be into 10 Be+n + γ on a 9 Be target. Interference between the multi-configurations of the projectile is observed as well as dynamical excitation of the core through the interaction with the target. MotivationThe exciting era introduced by the new radioactive beam facilities worldwide has pushed nuclear reaction theory to its limits of applicability [1,2]. Although significant progress has been achieved over the last decade, it is clear that nuclear reaction models are still lagging behind given the detail and quality of some coincidence measurements now available [3][4][5][6].Breakup reactions are frequently measured to provide structure information of the projectile, some of which hold relevance to astrophysics. When considering breakup of loosely bound core+N systems, one can describe the reaction process within a three body model, where the continuum is discretized in some way [7]. The coordinates used in such a model are represented in Fig. 1. If couplings are to be taken into account to all orders, one needs to solve the Continuum Discretized Coupled Channel (CDCC) Equation [7].In the past decade, the CDCC method has been applied to a very large number of reactions measured with radioactive beams, to help in the extraction of the desired structure information. Applications to the breakup of 6 Li and 6 He include Refs. [8][9][10][11][12] and results compare well with the data. One-neutron halo nuclei such as 11 Be and 15 C have also been studied within CDCC [13][14][15] and in most cases a good description of the data is found. Different targets and energy regimes have been used to study the breakup of the proton halo 8 B most of which have been analysed under the CDCC model [16][17][18][19][20][21].A new technique to explore the low lying continuum states of dripline nuclei (or nuclei beyond the dripline) involves transfer to the continuum. For example, to study states in the unbound system of 10 Li, which bares important information for the behaviour of the Borromean halo nucleus 11 Li, the (d,p) reaction is used on 9 Li, in inverse kinematics [23]. The final state in this transfer process can also be described within CDCC and applications *