ISOSPIN CONSERVATION AND THE NEUTRON HALO

Isospin breaking is studied in nuclei which are isobaric to light neutron-halo nuclei with the 1s single-neutron case Be-11 as an example. For this the total mixing probability into the daughter state increases with decreasing binding energy asymptotically reaching about 2 x 10(-4). The admixed intensity of the analogue state, which determine the rate of the Fermi beta decay, increases at first with decreasing binding and then passes through a rather flat maximum of about (1-2) x 10(-4) before it converges towards zero.