Elastic scattering of halo nuclei is one of the hot topics in nuclear physics. Many experimental and theoretical efforts have been done on the elastic scattering of neutron halo nuclei at energies near the Coulomb barrier and the suppression of the Coulomb rainbow peak is observed. However, the experimental researches for proton halo nuclei, especially on the medium-mass target nuclei, are very scarce. One of them is the research group from Institute of Modern Physics who has performed the experimental studies of the ⁸B and ¹⁰C at energies about three times of Coulomb barrier at the first Radioactive Ion Beam Line in Lanzhou (RIBLL1) and firstly observed a different behavior from the neutron halo nuclei. The researchers from Beihang University, China Institute of Atomic Energy and Institute of Modern Physics, China Academy of Science, have studied the elastic scattering of proton drip-line nucleus ¹⁷F on ⁸⁹Y experimentally at RIBLL1 and obtained the important results. 

The researches extend the experimental method and obtain the experimental data. It is found that the experimental data show a clear Coulomb rainbow peak. It is entirely different from the angular distribution of elastic scattering induced by neutron-halo nuclei which show the Coulomb rainbow suppression. It suggests that the multipole response of the neutron halo projectiles is stronger than that of the proton halo systems. These experimental results are very important for people to understand the nature of neutron halo and proton halo and their effects on the reaction.  

The results are published on Physical Review C 97, 044618 (2018), Nuclear Instruments and Methods in Physics Research Section A 846, 23 (2017) and Nuclear Science and Techniques 28, 104 (2017). 

Angular distribution of elastic scattering for 59MeV ¹⁷F on ⁸⁹Y target