Decay of the compound nucleus118*297formed in the reactionCf249+Ca48using the dynamical cluster-decay model

Abstract

The decay of the $Z=118$, $^{297}118^{*}$ compound system, formed in the $^{249}\mathrm{Cf}+^{48}\mathrm{Ca}$ reaction, is studied for $2n$, $3n$, and $4n$ emissions, by using the dynamical cluster-decay model (DCM) at compound-nucleus (CN) excitation energies ${E}_{\mathrm{CN}}^{*}=29.2$ and 34.4 MeV. A parallel attempt is made to analyze the $^{294}118$ residue nucleus synthesized in the $^{250}\mathrm{Cf}+^{48}\mathrm{Ca}$ reaction, subsequent to the $4n$ emission from the $^{298}118^{*}$ nucleus, to check the possibility of isotopic mixing in the $^{249}\mathrm{Cf}$ target used in the $^{249}\mathrm{Cf}+^{48}\mathrm{Ca}$ reaction. The possible role of deformations and orientations, together with different nuclear proximity potentials, is also investigated. In addition, an exclusive analysis of the mass distributions of $Z=113$ to 118 superheavy nuclei, formed in $^{48}\mathrm{Ca}$-induced reactions, is explored within the DCM. A comparative importance of Prox-1977 and Prox-2000 potentials on the $\ensuremath{\alpha}$-decay chains is also investigated, first by using the preformed cluster model (PCM) for spontaneous decays $(T=0)$, the $\mathrm{PCM}(T=0)$, and then analyzing the possible role of excitation energy in PCM, i.e., $\mathrm{PCM}(T\ensuremath{\ne}0)$, via the measured recoil energy of the residual $^{294}118$ nucleus left after $3n$ emission from $^{297}118^{*}$ CN. The branching of $\ensuremath{\alpha}$ decay to the most-probable clusters is also examined for $^{294}118^{*}$ and its subsequent $^{290}116^{*}$ and $^{286}114^{*}$ parents occurring in the $\ensuremath{\alpha}$-decay chain. Interestingly, the calculated decay half-lives for some clusters such as $^{86}\mathrm{Kr}$, $^{84}\mathrm{Se}$, and $^{80}\mathrm{Ge}$, referring to doubly magic $^{208}\mathrm{Pb}$ or its neighboring daughter nucleus, present themselves as exciting new possibilities, though to date difficult to observe, of heavy cluster emissions in superheavy mass region.