Enhanced production of unusually neutron-deficient heavy fragments was observed in the fission of the compound system formed in two different heavy-ion-induced reactions. The relative intensities of the fragments were determined from in-beam $\gamma$-ray spectroscopy with Gammasphere. Two peaks were observed in the distributions for Ba and Ce fission fragments. The lighter peak, comprised of neutron-deficient isotopes, cannot be reproduced by statistical calculations. A possible explanation of the enhanced production of these neutron-deficient heavy fragments is discussed.

• Received 20 November 2002

DOI:https://doi.org/10.1103/PhysRevC.67.034602