On the Experimental Identification of Spin-Parities and Single-Particle Configurations in $^{257}$No and Its $\alpha$-Decay Daughter $^{253}$Fm

摘要

Recently measured lifetimes of the favored $\alpha$ decays from $^{257}$Nohave been calculated using the quantum mechanical tunneling within WKBapproximation using microscopic nuclear potentials. Results obtained assumingpreviously assigned (ambiguous) parent spin of $\frac{7^+}{2}$ and newlyassigned configuration $\frac{3^+}{2}$ [622] have been compared. Hindrancefactors for the favored decays have also been compared with the calculatedhindrances using higher angular momenta transfers. Although the calculationssubstantiate the findings, yet it makes the spin-parity assignment of$\frac{3^+}{2}$ for the ground state of $^{257}$No less definite.