Search for a 7-α chain state

The reaction {sup 12}C({sup 16}O,7{alpha}) has been studied over the center-of-mass energy range from 37.7 MeV to 51.4 MeV, in a search for evidence for a 7-{alpha} chain state in {sup 28}Si. The yields of the {sup 12}C(0{sub 2}{sup +})-{sup 12}C(0{sub 2}{sup +})-{alpha} and {sup 12}C(0{sub 2}{sup +})-{sup 8}Be-{sup 8}Be final states agree broadly with previous measurements but contain no structure, indicating that a {sup 28}Si chain state is probably not being observed. The yields for the inelastic scattering reaction {sup 12}C+{sup 16}O decaying to other excited states in {sup 12}C and {sup 16}O have also been studied. They also contain no gross structure.