Examination of the fission time of the $Z=120$ nucleus

We show that the large difference in the measured lifetime for asymmetric fission of the highly excited ($T\approx 1.5\text{-MeV}$) $Z=120$ nucleus as measured by the atomic techniques (crystal blocking and x-ray methods) with those measured by the nuclear techniques (mass-angle distribution and prefission neutron multiplicity) cannot be due to the different sensitivities of the atomic and nuclear techniques in different time domains. The claim of formation of a superheavy $Z=120$ nucleus with a high fission barrier on the basis of an observed long fission time by the atomic techniques is in direct conflict with all other available measurements and calculations.

Figure 1

Percentage of the long-lived fission component $[f_L\left(\tau \right)\%]$ versus the fission time ($\tau$) obtained from Eq. (1) using the data of Fregeau et al. [9].

Figure 2

Fission lifetime versus prefission neutron multiplicity $\left({\nu }_{\mathrm{pre}}\right)$ for the ${}^{238}\mathrm{U}+{}^{64}\mathrm{Ni}$ reaction at $E{\left({}^{238}\mathrm{U}\right)}_{\mathrm{lab}}=6.6$ MeV/nucleon as obtained from the joanne2 code calculations.