α-decay chains of115173288and117228715in the relativistic mean field theory

Abstract

In the recent experiments designed to synthesize the element 115 in the $^{243}\mathrm{Am+}^{48}\mathrm{Ca}$ reaction at Dubna in Russia, three similar decay chains consisting of five consecutive $\ensuremath{\alpha}$ decays and another different decay chain of four consecutive $\ensuremath{\alpha}$ decays are detected, and the decay properties of these synthesized nuclei are claimed to be consistent with consecutive $\ensuremath{\alpha}$ decays originating from the parent isotopes of the new element 115, $^{288}115$ and $^{287}115$, respectively. Here in the present work, the recently developed deformed relativistic mean field$+$BCS method with a density-independent $\ensuremath{\delta}$ function interaction in the pairing channel is applied to the analysis of these newly synthesized superheavy nuclei. The calculated $\ensuremath{\alpha}$-decay energies and half-lives agree well with the experimental values and with those of the macroscopic-microscopic finite-range droplet model with folded-Yukawa single-particle potentials and Yukawa-plus-exponential model with Woods-Saxon single-particle potentials. In the mean field Lagrangian, the TMA parameter set is used. Particular emphasis is laid on the influence to both the ground-state properties and energy surfaces introduced by different treatments of pairing. Two different effective interactions in the particle-particle channel, i.e., the constant pairing and the density-independent $\ensuremath{\delta}$-function interaction, together with the blocking effect are discussed in detail.