| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
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| Research Abstract |
Particle-particle-gamma data from ^<28>Si + ^<28>Si molecular resonances was analised. By using R-matrix scattering amplitudes from high-spin molecular model, we can theoretically calculate gamma-ray intensities from the fragments ^<28>Si which are emitted from the resonance decays. The experimental data suggest "rn = 0" which, means the spins vectors of ^<28>Si are on the reaction plane. We studied what molecular normal modes exibits such a special nuclear structure.
Following mechanism has been expected to obtain the spins parallel to the plane; 1.the stable configuration of ^<28>Si + ^<28>Si is expected to be an equator-equator touching configuration, 2.such a stable configuration has a tri-axial deformation, 3.due to extremely high spin, rotation(J=38), the total deformed object rotates around the axis of highest moments of inertia, which give rise to K-mixing so called wobbling mode. Then the symmetry axes of two ^<28>Si are perpendicular to the plane, and the spin vectors are on the plane because they are orthogonal to the axes. Such a rotational mode is possible for the molecular ground state and the butterfly and anti-butterfly modes. We have also another mode twisting to obtain non-alignments by simpler mechanism, in which two ^<28>Si spin around the molecular axis in the opposite spin-vector directions. The vectors are parallel to the molecular axis which rotates on the reaction plane.
Comparing theoretical results with the data, we conclude that the molecular ground state with wobbling rotation is a candidate for the resonance structure. The other two are not good candidates by the following reason. In the butterfly mode and the twisting one the spin vectors are parallel to the fragment direction and the beam one, respectively. Even with the spins parallel to the reaction plane, we obtained no "m = 0" from too much concentrated vectors to own directions, because "m = 0" require "symmetry around z-axis".
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