A new fission mode in

Shell-driven fission modes result from the quantum mechanical many-body dynamics underlying nuclear fission. Their regions of influence, as well as the nuclear shapes they induce at scission, is a rapidly developing area of research. Evidence has emerged of novel fission modes in pre-actinide nuclei associated with Z≈36 and Z≈44. We present evidence of the Z=44 mode persisting up to 220Ra (Z=88). Being an example of bimodal symmetric fission, this result necessitated two-dimensional Gaussian fitting and a statistically rigorous data subsampling analysis to separate this novel mode from the liquid drop mode.