Coulomb breakup of 22C in a four-body model

TL;DR

This study models the Coulomb breakup of the Borromean nucleus 22C using a four-body eikonal approach, revealing how ground-state properties influence breakup behavior and suggesting a low-energy 2+ resonance.

Contribution

It introduces a four-body eikonal model with Coulomb corrections for 22C, incorporating hyperspherical coordinates and the R-matrix method to analyze breakup cross sections.

Findings

Low-energy E1 strength enhancement linked to binding energy.

Shape of low-energy cross section sensitive to ground-state properties.

Potential existence of a low-energy 2+ resonance in 22C.

Abstract

Breakup cross sections are determined for the Borromean nucleus 22C by using a four-body eikonal model, including Coulomb corrections. Bound and continuum states are constructed within a 20C + n + n three-body model in hyperspherical coordinates. We compute continuum states with the correct asymptotic behavior through the R-matrix method. For the n+ n potential, we use the Minnesota interaction. As there is no precise experimental information on 21C, we define different parameter sets for the 20C + n potentials. These parameter sets provide different scattering lengths, and resonance energies of an expected 3/2+ excited state. Then we analyze the 22C ground-state energy and rms radius, as well as E1 strength distributions and breakup cross sections. The E1 strength distribution presents an enhancement at low energies. Its amplitude is associated with the low binding energy, rather than with a three-body resonance. We show that the shape of the cross section at low energies is sensitive to the ground-state properties. In addition, we suggest the existence of a low-energy 2+ resonance, which should be observable in breakup experiments.