Thermal fission rate around superfluid-normal phase transition

Using Langer’s ImF method, we discuss the temperature dependence of nuclear fission width in the presence of dissipative environments. We introduce a low frequency cutoff to the spectral density of the environmental oscillators in order to mimic the pairing gap. It is shown that the decay width rapidly decreases at the critical temperature, where the phase transition from superfluid to normal fluids takes place. A possible relation to the recently observed threshold for the dissipative fission is discussed. © 1996 The American Physical Society.