Carbon-19 in Halo EFT: Effective-range parameters from Coulomb-dissociation experiments

TL;DR

This paper employs Halo EFT to analyze Coulomb dissociation data of 19C, extracting effective-range parameters and neutron separation energy, confirming the s-wave dominance in the halo structure.

Contribution

It introduces a Halo EFT approach to determine effective-range parameters and separation energy of 19C from experimental Coulomb dissociation data.

Findings

Neutron separation energy of 19C is 575 +/- 55(stat.) +/- 20(EFT) keV.

18C-neutron scattering length is 7.75 +/- 0.35(stat.) +/- 0.3(EFT) fm.

Predicted momentum distribution matches experimental data, confirming s-wave dominance.

Abstract

We study the Coulomb dissociation of the 19C nucleus in an effective field theory that uses the 18C core and the neutron as effective degrees of freedom and exploits the separation of scales in this halo system. We extract the effective-range parameters and the separation energy of the halo neutron from the experimental data taken at RIKEN by Nakamura et al. We obtain a value of (575 +/- 55(stat.) +/- 20(EFT)) keV for the one-neutron separation energy of 19C, and (7.75 +/- 0.35(stat.) +/- 0.3(EFT)) fm for the 18C-neutron scattering length. The width of the longitudinal momentum distribution predicted by EFT using this separation energy agrees well with the experimental data taken at NSCL by Bazin et al., reaffirming the dominance of the s-wave configuration of the valence neutron.