Universal geometry of two-neutron halos and Borromean Efimov states close to dissociation

• Published in: arXiv.org
• Main Author: Naidon, Pascal
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 10.07.2023
• Subjects: Angles (geometry); Field theory; Particle interactions; Particle physics; Physics - Nuclear Theory; Physics - Quantum Gases
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2302.08716

The geometry of Borromean three-body halos, such as two-neutron halo nuclei or triatomic molecules close to dissociation, is investigated using a three-body model. This model enables to analytically derive the universal geometric properties found recently within an effective-field theory for halos made of a core and two resonantly-interacting particles [Phys. Rev. Lett., 128, 212501 (2022)]. It is shown that these properties not only apply to the ground three-body state, but also to all the excited (Efimov) states where the core-particle interaction is resonant. Furthermore, a universal geometry persists away from the resonant regime between the two particles, for any state close to the three-body threshold. This "halo universality" is different from the Efimov universality which is only approximate for the ground state. It is explained by the separability of the hyper-radius and hyper-angles close to the three-body dissociation threshold.