# Extracting three-body breakup observables from CDCC calculations with core excitations

## TL;DR

This paper develops a method to extract detailed three-body breakup observables from CDCC calculations, incorporating core excitations, to better analyze reactions involving deformed weakly-bound nuclei.

## Contribution

It extends the CDCC framework to include core excitations for computing detailed two- and three-body breakup observables in nuclear reactions.

## Key findings

- Core excitations significantly affect breakup cross sections with proton targets at intermediate energies.
- Core excitations have minimal impact on reactions with Zn targets near the Coulomb barrier.
- The method enables detailed analysis of breakup reactions with deformed weakly-bound nuclei.

## Abstract

Core-excitation effects in the scattering of two-body halo nuclei have been investigated in previous works. In particular, these effects have been found to affect in a significant way the breakup cross sections of neutron-halo nuclei with a deformed core. To account for these effects, appropriate extensions of the continuum-discretized coupled-channels (CDCC) method have been recently proposed. We aim to extend these studies to the case of breakup reactions measured under complete kinematics or semi-inclusive reactions in which only the angular or energy distribution of one of the outgoing fragments is measured. We use the standard CDCC method as well as its extended version with core excitations (XCDCC), assuming a pseudo-state basis for describing the projectile states. Two- and three-body observables are computed by projecting the discrete two-body breakup amplitudes, obtained within these reaction frameworks, onto two-body scattering states with definite relative momentum of the outgoing fragments and a definite state of the core nucleus. The presented method provides a tool to compute double and triple differential cross sections for outgoing fragments following the breakup of a two-body projectile, and might be useful to analyze breakup reactions with other deformed weakly-bound nuclei, for which core excitations are expected to play a role. We have found that, while dynamical core excitations are important for the proton target at intermediate energies, they are very small for the Zn target at energies around the Coulomb barrier.