Ronen's golden rule for cluster radioactivity

In nuclear physics, Ronen's golden rule for cluster radioactivity is that the most favorable parents for heavy ion emission (cluster radioactivity) are those that emit clusters which have atomic mass ${\displaystyle A_{z}}$ which is given by ${\displaystyle A_{z}=A_{z-2}+4+B_{z/2}}$. The atomic number ${\displaystyle Z}$ is even, ${\displaystyle A_{0}=0}$, ${\displaystyle B_{z/2}=0}$ for ${\displaystyle Z/2}$ - odd and ${\displaystyle B_{z/2}=2}$ for ${\displaystyle Z/2}$ - even. The daughter nuclei is preferably magic, close to the double magic ²⁰⁸Pb.