Radii of the bound states in 16N from the asymptotic normalization coefficients

The asymptotic normalization coefficients (ANCs) of the virtual decay ¹⁶N→¹⁵N+n are extracted from the ¹⁵N(⁷Li, ⁶Li)¹⁶N reaction populating the ground and first three excited states in ¹⁶N. The root-mean-square (rms) radii of the valence neutron in these four low-lying ¹⁶N states are then derived by using the ANCs. The probabilities of the valence neutron staying out of the core potentials are found to be 31%±8%, 58%±12%, 32%±8%, and 60%±12%. The present results support the conclusion that a one-neutron halo may be formed in the ¹⁶N first and third excited states, while the ground and second excited states do not have a one-neutron halo structure. However, the core excitation effect has a strong influence on the one-neutron halo structure of the ground and first excited states in ¹⁶N.