Few-Nucleon Scattering Experiments to Explore the Three-Nucleon Forces

In pursuit of establishing a high-precision three-nucleon force (3𝑁F) potential within the framework of chiral effective field theory (𝜒EFT), we plan to acquire new data on the spin correlation coefficients in deuteron-proton (𝑑-𝑝) elastic scattering at 100 MeV/nucleon. We have developed a solid-state polarized proton target and the KuJyaku detector system for this purpose, whose performances were evaluated in the deuteron-polarized proton scattering experiment at the RIKEN RI Beam Factory in January 2024. The angular distributions of the preliminary differential cross-section and proton analyzing power results exhibit close agreement with existing data, suggesting successful identification of 𝑑-𝑝 elastic events using the KuJyaku system. However, the extracted polarization of the new target system was at 3%, and efforts are currently underway to increase this polarization aiming to achieve high precision in the forthcoming spin correlation coefficient measurements.