Super-heavy nuclei of interest for the forthcoming synthesis of the isotopes with $Z=119$, 120 are investigated. One of the very interesting latest experiments was performed at the velocity filter SHIP (GSI Darmstadt) trying to produce ${}^{299}120$ in a fusion reaction ${}^{248}\mathrm{Cm}({}^{54}\mathrm{Cr},3\mathrm{n}){}^{299}120$. We report calculations of $\alpha$-decay half-lives using four models: AKRA (Akrawy), ASAF (analytical superasymmetric fission), UNIV (universal formula), and semFIS (semi-empirical formula based on fission theory). The released energy, $Q$, is calculated using the theoretical model of atomic masses, WS4. For ${}^{92,94}\mathrm{Sr}$ cluster radioactivity of ${}^{300,302}120$ we predict a branching ratio relative to $\alpha$ decay of $-0.10$ and 0.49, respectively, meaning that it is worth trying to detect such kinds of decay modes in competition with $\alpha$ decay.

• Received 26 February 2018

DOI:https://doi.org/10.1103/PhysRevC.97.044621