Structure of the spatial periphery of the 11Li and 11Be isobars

Abstract

On the basis of the shell model with an extended basis, the structure of 9Li-9Be to 11Li-11Be nuclei is examined with allowance for the competition of jj coupling and Majorana exchange forces via considering the sequential addition of neutrons, and the respective wave functions are determined. A formalism for calculating the spectroscopic factor for a dineutron and for individual neutrons in nuclei whose wave functions incorporate the mixing of shell configurations is developed. The reactions 9Li(t, p)11Li and 9Be(t, p)11Be treated with allowance for the mechanisms of dineutron stripping and a sequential transfer of two neutrons are considered as an indicator of the proposed structure of lithium and berylliumisotopes. The parameters of the optical potentials, the wave functions for the bound states of transferred particles, and the interaction potentials corresponding to them are determined from a comparison of the theoretical angular distribution of protons from the reaction 9Be(t, p)11Be with its experimental counterpart. It is shown that a dineutron periphery of size about 6.4 fm is present in the 11Li nucleus and that a single-neutron periphery of size about 8 fm is present in the 11Be nucleus.