Exploring Scaling Laws of Valence Neutron Distributions for Medium Nuclei

The root-mean-square radii of the valence neutron distributions for many nuclei in He-Mo mass range are calculated in the framework of the single-particle potential model. The scaling laws of valence neutron distributions are obtained by analyzing the relations between the radii and the binding energies of the valence neutrons. Based on these scaling laws, the necessary conditions for the occurrence of neuron halos in 2s_1/2, 1p_3/2, 1p_1/2, 2p_3/2, 2p_1/2, 1d_5/2 and 1d_3/2 states are deduced, respectively. The derived quantitative conditions for halo occurrence can provide reference for the searching of neutron halos up to medium nuclei.