Isospin in halo nuclei: Borromean halo, tango halo, and halo isomers

Abstract

It is shown that the wave functions for isobaric analog, double isobaric analog, configuration, and double configuration states may simultaneously have components corresponding to nn, np, and pp halos. The difference in the halo structure between the ground and excited states of a nucleus may lead to the formation of halo isomers. A halo structure of both Borromean and tango types can be observed for np configurations. The structure of ground and excited states with various isospins in halo-like nuclei is discussed. The reduced probabilities B(Mλ) and B(Eλ) for gamma transitions in ⁶⁻⁸Li, ⁸⁻¹⁰Be, ^8,10,11B, ¹⁰⁻¹⁴C, ¹³⁻¹⁷N, ^15−17,19O, and ¹⁷F nuclei are analyzed. Particular attention is given to the cases where the ground state of a nucleus does not have a halo structure, but where its excited state may have it.