Narrow Results

The $\alpha$-decay chain of ${}^{314-340}126$ and ${}^{350-400}138$ is studied using cubic plus proximity potential with improved transfer matrix (CPP-ITM) model. The nuclear mass models DD-PC1, WS4, WS3.3 are employed to evaluate the $\alpha$-decay energies. Thus calculated $\alpha$-decay half-lives and decay chain lengths are found to be in good agreement with other theoretical formalisms. The spontaneous fission (SF) half-lives are calculated using the formalism of Xu et al. [Phys. Rev. C71 (2005) 014309; Phys. Rev. C78 (2008) 044329] to have a vision on the possible decay modes and decay chain lengths, and the most probable decay chains associated with the isotopes of $Z=126$$\&$$138$. This paper unveils the mass region that survives fission and also predict the long $\alpha$-decay chains of $Z=126$$\&$$138$ with ${}^{314}126$ emitting 6$\alpha$, ${}^{316\&318}126$ emit 5$\alpha$$\&$${}^{320}126$ 4$\alpha$ particles, while for ${}^{350,352,354,356\&358}138$ chains will have $8,7,6,5\alpha$ emission. The SF for $Z=126$$\&$$138$ occur at $A\ge 330$ and $A\ge 372$. These current predictions may pave way to detect/synthesize the most probable isotopes of the superheavy elements $Z=126$$\&$$138$ in the laboratory through future experiments.

One of the substantial successes achieved in nuclear physics in the last two decades was the synthesis of dozens of isotopes of new elements up to ${}_{118}$Og, which closed the seventh row of the periodic table and inspired the ambition of adding more elements. This work aims to study extensively the ground state structure and decay properties of proposed $Z=120$ isotopes. We employed Macroscopic–microscopic scheme based on the Skyrme energy density functional, the Woods–Saxon single-particle potential and Strutinsky’s method to find the structure properties, in a multidimensional deformation space. The same nucleon–nucleon potential is used to find the $\alpha$-decay half-life, within the Preformed Cluster Model. For 45 ${}^{270-314}$120 isotopes, the total energy surfaces, ground state masses, binding energy, deformations and fissionability are determined. The $Q$-values of the different competing decays and $\alpha$-decay half-lives are investigated based on the obtained structure. The results indicate the ${}^{294-300}$120 isotopes to be the most bound among the studied isotopes. The smallest fission barriers are indicated for the ${}^{285-294,296,313}$120 isotopes. The ${}^{294-304}$120 isotopes showed the longer half-lives against $\alpha$-decay, with an order of $\mu \mathrm{\text{s}}$. The longest half-lives are estimated for the ${}^{301}$120 ($3.7\pm 3.6\mu \mathrm{\text{s}})$ and ${}^{304}$120 ($1.1\pm 1.0\mu \mathrm{\text{s}})$ isotopes. The longest full decay chain ending with the stable ${}^{207}$Pb nucleus is anticipated for the ${}^{295}$120 isotope. The shortest decay chain of ${}^{296}$120 terminates after three $\alpha$-decays by the spontaneous fission of ${}^{284}$Fl.