Equation 9.11.486E82FAF4001B

\begin{equation} \frac{\beta ^2}{2}=\frac{|t|^2(1+4|z|^2+|z|^4)}{\pi ^2(1+|t|^2(1+|z|^2+|z|^4))^3}\, \mathrm{d}\lambda _4. \end{equation}