One-proton halo in Cl-31 with relativistic mean-field theory

We investigate proton-rich isotopes Cl-31,Cl-32 using the nonlinear relativistic mean-field model. It is shown that this model can reproduce the properties of these nuclei well. A long tail appears in the calculated proton density distribution of Cl-31. The results of relativistic density-dependent Hartree theory show a similar trend of tail density distribution. It is strongly suggested that there is a proton halo in Cl-31 and it is indicated that there may be a proton skin in Cl-32. The relation between the proton halo in Cl-31 and the new proton magic number is discussed.