Halo-like Structures Observed in ²⁰⁹Pb

The density distributions of the last neutron in ²⁰⁹Pb wereinvestigated by analysis of the ²⁰⁸Pb(d,p)²⁰⁹Pb transfer reactions at 8 MeV. The results show that the last neutron in the 2d_5/2,3s_1/2,1g_7/2 and 2d_3/2 states is present with appreciable probability at distances much larger than the core radius. Therefore, these states should be the neutron halo or skin states. Moreover, the density distributions extracted illustrate that there is intrinsic relationship between the node number of state and the halo formation.