Three-body analysis reveals a significant contribution of a minor He 5 s -wave component in the Li 6 (p,2p) He 5 cross section

Background: Li6 is usually treated as an α+p+n three-body system, and the validity of this picture is important for understanding Li6 reactions. The (p,2p) reaction is a powerful method to study the structure of valence nucleons in Li6. Recently, the new experimental data of the Li6(p,2p)He5 reaction have been obtained and should be analyzed. Purpose: We investigate the Li6(p,2p)He5 reaction using the α+p+n three-body wave function of Li6 and study the validity of this model. Methods: We calculate the Li6 wave function by using the Gaussian expansion method, and the function is used to obtain the relative wave function between p and He5. We combine the relative wave function with the distorted wave impulse approximation. Results: Our results reproduce the experimental data of the triple differential cross section within about a 10% difference in the absolute values, and contributions from both p- and s-wave states of He5 in Li6 are found to be important. Conclusions: We can qualitatively understand the Li6(p,2p)He5 reaction by describing Li6 with the three-body model. Contribution from the s-wave component is important in reproducing the experimental data in the zero recoil-momentum region.