Study of halo structure of ¹⁶C from reaction cross section measurement

The reaction cross sections for ^12,16C have been measured at the energy of 83 A MeV by a new experimental method. The larger enhancement of the ¹⁶C reaction cross section at the low energy has been used to study the density distribution of ¹⁶C. The finite-range Glauber-model calculations for different density distributions have been compared with the experimental data. The analysis suggests that ¹⁶C mainly has a ¹⁴C(core)+2n structure and shows a strong contribution of (2s_1/2)² for valence neutrons. A large extension of the neutron density distribution to a distance far from the center of the nucleus suggests the formation of neutron halo in the ¹⁶C nucleus.