用转移反应研究~6He奇特核体系的光学势

Study of Optical Potential of ~6He Halo Nuclear System by Transfer Reaction

由于受到放射性束强度弱、品质差的限制,奇特核体系的光学势性质一直是亟待解决的国际难题。本工作利用稳定束的转移反应作为探针,深入研究了反应出射道奇特核体系的光学势性质。利用中国原子能科学研究院的HI-13串列加速器在近库仑位垒能区高精度测量了7Li+63Cu、208Pb的弹性散射以及单质子转移反应角分布,并利用扭曲波玻恩近似(DWBA)和耦合反应道(CRC)方法对实验数据进行了拟合,抽取了出射道6He+64Zn、209Bi晕核体系的光学势参数。所得参数可重现文献中已有的6He体系的弹性散射角分布,验证了这种方法的可靠性。对所得势参数的能量相依性的分析表明,在重体系6He+209Bi中,基于因果律的色散关系并不适用,其潜在的物理原因还需进一步深入研究。

Due to the limits of the intensity and quality of the radioactive ion beams,it is difficult to extract the reliable optical potentials of halo nuclei directly from elastic scattering measurements.Therefore,it is still a challenging task to study the properties of the optical potentials of halo nuclear systems.The optical potentials of 6He halo nuclear systems were extracted by measuring the transfer reactions with stable beams.The angular distributions of elastic scattering and one-proton transfer reactions of 7Li + 63 Cu and 208 Pb were measured at energies around the Coulomb barrier.The optical potentials of 6He + 64 Zn and 209 Bi systems in the exit channel were extracted by fitting the transfer reaction data with the distorted-wave Born approximation (DWBA) and coupled reaction channels (CRC) methods,respectively.The derived potential parameters can reproduce the existing experimental elastic scattering data at the corresponding energies,which verifies the validity of the transfer reaction method.According to the energy dependence of the optical potentials,it’s found that the dispersion relation,which is based on the causality principle,is not applicable for the 6He + 209 Bi system.The possible explanations for such a peculiar behavior were discussed,but further study is still desired for the underlying physics.