α decay and spontaneous fission half-lives of nuclei around 270Hs

alpha decay and spontaneous fission half-lives of 81 superheavy nuclei with Z = 104-112 and N = 158-166 have been calculated with simple formulas extracted from the systematics of measured and calculated half-lives. Half-life calculations are performed within the shell model and one-body rate theories for alpha decay and a dynamical approach for spontaneous fission defined essentially by the shape, the height of fission barrier, the fissility, and the nuclear deformations. We obtained a rather good accordance between calculated and experimental half-lives for 30 nuclei with measured Q(alpha) values. We predicted with different fitting formulas the most probable half-lives for 51 nuclides at which there are no experimental data. The rms values for experimental and theoretical half-lives are evaluated and discussed. The comparison of theoretical calculations with experimental data allows us to draw conclusions on the role of the nuclear structure and shell effects in low-energy decay processes.