A short-range effective theory for single-neutron halo nuclei with a deformed core
Abstract
We establish a short-range effective theory for deformed s-wave halos. The theory applies to a system in which neutrons are weakly bound to a core nucleus, and that core nucleus also exhibits a low-lying rotational band with a 0+ ground state and a first 21+ excited state. The effective theory then must have both halo degrees of freedom and degrees of freedom associated with rotation of the core. This leads to the particle plus rotor model of Bohr and Mottelson at leading order. We identify the relevant leading-order operators in the Hamiltonian that respect the symmetries of the system and the small parameters which define the effective theory's power counting. We carry out calculations for the 11Be and 17C systems in which we compute the low-lying positive-parity states of the core + neutron systems up to the core(21+)-neutron threshold. We do this for several different regulator parameters and establish that these energies can be renormalized using the leading-order set of operators. The spectrum is accurately described at leading order in both cases. Decay widths to d-wave core-neutron states have sizable cutoff dependence, but the Asymptotic Normalization Coefficients (ANCs) in s-wave channels exhibit regulator dependence of a size consistent with next-to-leading-order effects. We also compute Coulomb breakup observables and compare with experimental data, finding leading-order results in reasonable agreement with data for both 11Be and 17C. The addition of one next-to-leading-order operator renders the ANCs of all s-wave states stable with respect to the regulator. It consequently also removes most of the 30\% variation of the leading-order Coulomb dissociation cross section with the regulator.
Related
- Nuclear mass table in deformed relativistic Hartree-Bogoliubov theory in continuum, III: nuclei with 8 ≤ Z ≤ 120
- Dynamical tidal response of neutron stars: From effective field theory to gravitational waveforms
- Deformed self-consistent Green's function method for atomic nuclei at second and third order in the algebraic diagrammatic construction
- Puzzling isotonic odd-even staggering of charge-radii in deformed rare earth nuclei
- Theoretical study of normal deformed rotational bands of odd-mass 167,169,171Lu nuclei
BibTeX
@misc{kubushishi2026shortrange,
title = {{A short-range effective theory for single-neutron halo nuclei with a deformed core}},
author = {Live-Palm Kubushishi and Daniel R. Phillips},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.21547},
eprint = {2606.21547},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.21547},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A short-range effective theory for single-neutron halo nuclei with a deformed core
AU - Live-Palm Kubushishi
AU - Daniel R. Phillips
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2606.21547
UR - https://arxiv.org/abs/2606.21547
AB - We establish a short-range effective theory for deformed s-wave halos. The theory applies to a system in which neutrons are weakly bound to a core nucleus, and that core nucleus also exhibits a low-lying rotational band with a 0^+ ground state and a first 2_1^+ excited state. The effective theory then must have both halo degrees of freedom and degrees of freedom associated with rotation of the core. This leads to the particle plus rotor model of Bohr and Mottelson at leading order. We identify the relevant leading-order operators in the Hamiltonian that respect the symmetries of the system and the small parameters which define the effective theory's power counting. We carry out calculations for the ^11Be and ^17C systems in which we compute the low-lying positive-parity states of the core + neutron systems up to the core(2_1^+)-neutron threshold. We do this for several different regulator parameters and establish that these energies can be renormalized using the leading-order set of operators. The spectrum is accurately described at leading order in both cases. Decay widths to d-wave core-neutron states have sizable cutoff dependence, but the Asymptotic Normalization Coefficients (ANCs) in s-wave channels exhibit regulator dependence of a size consistent with next-to-leading-order effects. We also compute Coulomb breakup observables and compare with experimental data, finding leading-order results in reasonable agreement with data for both ^11Be and ^17C. The addition of one next-to-leading-order operator renders the ANCs of all s-wave states stable with respect to the regulator. It consequently also removes most of the 30\% variation of the leading-order Coulomb dissociation cross section with the regulator.
ER -