Evidence for a New Reaction Mechanism in the Bombardment ofU238with 11.5-GeV Protons

Abstract
The masses and kinetic energies of coincident heavy fragments emitted from a U239 target bombarded with 11.5-GeV protons were measured as a function of the angle between the fragments. Fragments with nearly equal and opposite laboratory momenta are observed with a total mass as low as ∼ ½ that of the target and higher kinetic energy than expected from fission, providing evidence for a new reaction mechanism.