Nonequilibrium light particles were detected in coincidence with two fission fragments for ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$-induced reactions on ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ at 420 MeV incident energy. Coincident binary-fission events were used to define the reaction plane and to suppress contributions from transfer-like peripheral reactions. A strong preference for the emission of nonequilibrium light particles in the fission plane was observed, suggesting the presence of an ordered transverse motion of the emitting source in the reaction plane.

• Received 24 January 1984

DOI:https://doi.org/10.1103/PhysRevLett.52.1967