Simplified dynamical eikonal approximation

TL;DR

This paper introduces a simplified dynamical eikonal approximation (S-DEA) that improves the accuracy and efficiency of modeling nuclear and Coulomb breakup reactions of halo nuclei, addressing limitations of existing eikonal models.

Contribution

The paper develops a new simplified dynamical eikonal approximation (S-DEA) that enhances modeling of breakup reactions with similar computational cost as the standard eikonal model.

Findings

S-DEA provides precise energy distributions for breakup reactions.

S-DEA improves the shape and magnitude of parallel-momentum distributions, especially for nuclear-dominated reactions.

The model confirms dynamical effects cause asymmetry in momentum distributions.

Abstract

Background: Breakup reactions are often used to probe the nuclear structure of halo nuclei. The eikonal model diverges for Coulomb breakup since it relies on the adiabatic approximation. To correct this weakness, a Coulomb-corrected eikonal method (CCE) using the Coulomb first-order-perturbation approximation was developed. Purpose: Since the CCE mixes two reaction models and treats the Coulomb and nuclear interactions on different footings, we study here an alternative approach. We develop a simplification to the dynamical eikonal approximation (S-DEA) which has a similar numerical cost as the usual eikonal model, and study its efficiency for both nuclear- and Coulomb-dominated breakup reactions. Methods: We compare the energy and parallel-momentum cross sections obtained with the dynamical eikonal approximation, the usual eikonal approximation, the CCE and the S-DEA. Results: The S-DEA leads to precise energy distributions for both breakup reactions. The corresponding parallel-momentum distributions obtained with the S-DEA are improved compared to the ones computed with the eikonal model. It is more efficient for nuclear-dominated breakup than the CCE since it reproduces better the shape and magnitude of the distribution. However, for the Coulomb breakup, the distribution lacks asymmetry. Conclusions: The simplification of the DEA developed in this work improves significantly the eikonal descriptions of breakup energy distribution for both Coulomb- and nuclear-dominated reactions. The asymmetry of the parallel-momentum distribution is enhanced for nuclear-dominated breakup. This study confirms that the asymmetry is due to dynamical effects. A direct prospect of this work would be to extend this model to two-neutron halo-nucleus projectiles.