Spin dependence of the isospin-forbidden decay /sup 8/Be(E-italic/sub x-italic/ = 27. 5 MeV). -->. d+/sup 6/Li

The first T-italic = 2 state in /sup 8/Be (E-italic/sub x-italic/ = 27.483 MeV) has been studied by means of the isospin-forbidden resonance in the reaction d+ /sup 6/Li..--> cap alpha..+..cap alpha... Angular distributions of the cross section and of the four analyzing powers for the reaction /sup 6/Li(d-arrow-right,..cap alpha..) /sup 4/He have been measured at energies above, below, and on resonance. Off-resonance analyzing power measurements have also been obtained for /sup 2/H(/sup 6/Li-arrow-right,..cap alpha..) /sup 4/He. Because of the symmetry properties of the reaction, the number of independent collision matrix elements is fairly small, and this makes it possible to determine the matrix elements directly by fitting the data. By comparing the matrix elements, one can determine partial widths (GAMMA/sub 0/ and GAMMA/sub 2/) for decay of the /sup 8/Be state into d+ /sup 6/Li states with channel spin 0 and 2. The measured ratio of the partial widths is GAMMA/sub 2//GAMMA/sub 0/ = 0.322 +- 0.091.