The Neutron Structure of the Ground State of 7He

A study of the neutron structure of the ground state of 7He has been performed by means of registration and analysis of the decay channels of the residual nuclei following absorption of stopped pions. In particular, the reactions 9Be(π−, d)X and 11B(π−, dd)X have been investigated where X denotes any system with five neutrons and two protons — the constituencies of a 7He nucleus. The results point out to the existence of a halo-like configuration of the ground state of 7He with all three neutrons outside of the alpha particle core. The structure of this complicated halo-like state is determined by the correlations of neutrons in the p3/2 and p1/2 shells. The result would be in agreement wit…