Halo Structure In Light Nuclei Studied With Relativistic Continuum Hartree-Bogoliubov Theory

Based on the relativistic continuum Hartree-Bogoliubov theory, the neutron halo and the proton halo were discussed in this paper. Pairing correlations are taken into account by a density dependentδforce with zero range. We used single-particle blocking effects for the odd nucleon, neglecting the pairing correlation effects. In the first part, the ground state properties of the isotopes with proton number 3≤Z≤14 are studied with the nonlinear effective interaction NLLN. The results show that the 11Li, 11,14Be,17,19B,23,24O,31F and 31,32,34Ne have neutron halo structure, and the lighter nuclei are more easy to form neutron halo. With the proton number increases, the root mean square radius and the density distribution are similar, such as Na, Mg, Al and Si isotopes. In 42,43Al and 43,44,46Si, there have mutations trend, but the mutations are not obviously. Whether they having halo structure or not, need to be examined in further study. Neutron-rich nuclei in these isotopes chain are more likely to form the neutron skin structure. Analysing the phenomenon of light halo nuclei, we find it is a common phenomenon in the drip line nucleus.In the second part, we study the ground states of the C isotope chain (9≤A≤12), N=3 isotone chain and its mirror nucleus. The matter, neutron and proton rms radius, the density distributions, and energy level structure are studied. It shows 9C has a large rms radius of proton and low-density distributions tail. It indicated 9C may be a proton halo nucleus, which formed by p orbital low centrifugal barrier, the small binding energy and pairing correlation effects. We study the influence of the parameters and the potential strength Vp on the nature of proton halo nuclei 9C. The results show that 9C is a proton halo, and the proton halo structure is not sensitive to the choice of parameters. The formation of 9C proton halo is due to valence proton occupied the P3/2 orbit with a low centrifugal barrier. Pairing correlations lead to a scattering of Cooper pairs to the continuum state of p1/2 orbit, then the low density distribution appears to form a proton halo structure. Finally, the density distributions of 9C and that of the typical proton halo nucleus B are compared. The cross sections based on the Glauber model calculations with the density obtained from RCHB are directly compared with the experimental data. There are conclusions as follow:(1) the experimental results indicate that 9C is a two-proton nucleus, while 8B is a one-proton nucleus; (2) coupling between the different core of to proton halo nucleus and their valence proton leads to the core change correspondingly; (3) our RCHB calculated results are in very good agreement with the experimental data, so the theory can well describe 9C and 8B proton halo structure.