My research interest is to understand the forces acting in nuclei, so-called “nuclear force”. Particularly, I am interested in clarifying the roles of three-nucleon forces. The atomic nucleus consists of nucleons (protons and neutrons). The first fundamental idea of nuclear force was given by Prof. Hideki Yukawa in 1935. What he suggested is that ‘nuclear force is mediated by exchanging a vertical particle “meson” between two nucleons’. Since then the nuclear force has been taken as two-nucleon force (two-body force) in principle.
After 80 years of Yukawa’s meson theory, thanks to large progress of experiment, observation, and theory, the nuclear physics has achieved to a very exciting phase. It has turned out that various nuclear phenomena cannot be explained by the two-nucleon force, and the importance of three-nucleon force mediated by existence of the third nucleon has been pronounced. For instance, the three-nucleon force is considered to be a key element in understanding the properties of neutron-rich nuclei, that is the nuclei playing crucial roles in nucleosynthesis, and the neutron star. Meanwhile there are a few rooms to approach to the three-nucleon force experimentally.
In order to approach to the three-nucleon force and pin down the properties of this force, our group is now promoting experimental programs of few-nucleon scattering systems at the Cyclotron Radio-isotope Center (CYRIC) in Tohoku University, RCNP in Osaka University, and RIKNE RI Beam Factory. Currently we are constructing the polarized 3He target system for our experiments. We can order the technical staffs of the glass laboratory to form the glass target cells which are not available in the market. We can perform experiments of the target system by using the accelerator at CYRIC. Our research is fully supported by the local facilities and technical staffs, that is one of big advantages of Tohoku University.

When I was a graduate student, two theory groups reported signatures of three-nucleon force in deuteron-proton elastic scattering. Following my supervisor’s suggestions, I first started preparing the proposal for RIKEN Accelerator Research Facility to test the theory of three-nucleon force experimentally. This was good experience for me because I learned a lot, that is, what is of interest and of importance in physics, how we perform the experiment etc... Thanks to many supports from my collaborators the proposal was successfully approved. We could conduct high precision experiments and find significant signatures of three-nucleon forces.
I am so happy that I could start the study at the very beginning of discussions on three-nucleon force and still I enjoy very much.

I think having a wonderful encounter, which could be translated as “出会い” in Japanese, is important. I mean that is having an encounter not only with great people but also with something new or unexpected. If you could find even one in which you are engrossed or absorbed through “出会い”, I think that the thing could be your treasure in your life. I hope that you have a wonderful encounter with things, events, and people in your university life.