Study of the spin structure of Helium-3 nucleus and the non-nucleonic degree of freedom.

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1.Cross section and all of spin observables were measured for the pd elastic scattering with 250 MeV polarized protons. Experimental results were compared to Faddeev calculations and effects of three nucleon forces were discussed.2.Cross section and polarization were measured for the elastic scattering of 450 MeV ^3He off ^<12>C, ^<58>Ni and ^<90>Zr. A ^3He polarimeter was newly developed. This is the first measurements of the spin observables for the ^3He scattering at the intermediate energies. Spin dependent optical potentials were obtained by fitting experimental results.3.A spin exchange type polarized ^3He target was developed. Computer control system was constructed to optimize the diode laser performance, temperatures of the pumping cell, and optical components.4.Theoretical framework was investigated to describe the p-^3He elastic backward scattering. It takes account of two-nucleon exchange processes in both the triplet and the singlet state. Non nucleonic degree of freedom, π-meson exchanges, is also included in the calculation.5.The absolute polarization was calibrated by measuring the spin correlation parameter C_<yy> of ^3He(p,π^+)^4He reaction at 300 and 400 MeV. The result was consistent with measurements with the NMR method.6.The spin correlation parameter C_<yy> was measured for the p-^3He elastic backward scattering at 200, 300 and 400 MeV. Preliminary results were presented at the meeting of the Physical society of Japan. Detailed analysis is in progress now.7.Theoretical investigation is continued to clarify the effect of ^3He wave functions on the parameter C_<yy>.8.The experimental research is expected to be performed at higher energies.