Alpha-gamma decay studies of 258Db and its (grand)daughter nuclei 254Lr and 250Md

The superheavy isotope 258Db was produced in the 209Bi(50Ti, 1n)258Db reaction at GSI, Germany. A detailed \( \alpha\)-spectroscopy study of this isotope and its \( \alpha\)-decay daughter products was performed. Two long-lived \( \alpha\)-decaying states in 258Db are observed. A spin-parity of \( 0^{-}\) is tentatively assigned to the ground state for which a half-life of \( 2.17 \pm 0.36\) s is determined. Spins and parities of either \( 5^{+}\) or \( 10^{-}\) are proposed for the isomeric state found at an excitation energy of 51 keV with a half-life of \( 4.41 \pm 0.21\) s. The \( \alpha\) -decay daughter isotope 254Lr displays a similar behavior. A half-life of \( 11.9 \pm 0.9\) s is determined for the 254Lr ground state which is tentatively assigned a spin-parity of \( 4^{+}\). The isomeric level of this isotope placed at 108 keV with a half-life of \( 20.3 \pm 4.2\) s is tentatively assigned a spin-parity of \( 1^{-}\). Two long-lived \( \alpha\)-decaying states are observed in the granddaughter isotope 250Md . The ground state has a half-life of \( 59.5 \pm 9.1\) s. A half-life of \( 42.4 \pm 4.5\) s is measured for the isomeric state positioned at an excitation energy of 123 keV. Partial, tentative level schemes for 254Lr, 250Md and 246Es are proposed based on the \( \alpha\)-\( \gamma\) coincidences.