NEW APPROACH TO SPIN ASSIGNMENTS OF INTERMEDIATE STRUCTURES IN C-12(O-16,C-12[2(1)+])O-16

Magnetic substate populations for the 2+ state at 4.44 MeV in C-12 were measured in resonant C-12 + O-16 inelastic scattering by the gamma-ray recoil method. The m-substate population has been determined in the coordinate frame where a quantization axis is taken along the center of mass scattering angle of a reaction product. This coordinate frame gives an advantage that a resonance spin J can be obtained directly from m-substate angular distributions compared with the beam-axis frame. In addition a decay L value is sensitive to the relative intensity between each m-substate cross section. Our data suggest a spin assignment of J(pi) = 16+ or 17- for the structures at E(c.m.) = 29.8 MeV and 31.8 MeV. Both structures are determined to decay dominantly through the aligned configuration of L = J - 2.