Systematic study of the widths of fission fragment mass distributions of neutron deficient compound nuclei in the medium mass region

We have performed a systematic study of the widths of measured fission fragment mass distributions (FFMDs) from the fission of compound nuclei (CN) in the pre-actinide region in the overlapping excitation energy domain. The study has been performed for different reaction variables, such as the relative value of entrance channel mass asymmetry ( α ) w. r. t. Businaro–Gallone mass asymmetry ( α _BG ) or projectile-target charge product Z_ PZ_ T , N / Z ratio and excitation energy of the fissioning nuclei. In many cases, anomalous behaviour of the mass width with excitation energy of the fissioning nuclei indicates signatures of a non-equilibrated fission process or mass asymmetric fission. The present study shows the systematic dependence of reaction mechanism in such reactions on entrance channel parameters, i.e., entrance channel mass asymmetry, N / Z ratio and excitation energy of fissioning nuclei. The observed general behaviour of reactions studied w. r. t. different entrance channel parameters chosen for the present study shows the characteristic behaviour of CN fission but with certain exceptions, where mass widths show anomalies in the studied energy domain.