\midheading{$e^- \bar{\nu}_{e} \mu^- \bar{\nu}_{\mu} $-pair production via WBF, processes 229,2291}
The {\it weak} process ({\tt nproc=229})  occurs in $O(\alpha^6)$,
whereas the {\it strong} process occurs ({\tt nproc=2291}) in $O(\alpha^4 \alpha_S^2)$.  
These processes can currently only be calculated at lowest order.
\begin{eqnarray}
& 229 &   f(p_1)+f(p_2) \to W^-(e^-(p_3),\bar{\nu}_e(p_4)))W^+(\mu^-(p_5),\bar{\nu}_\mu(p_6))+f(p_7)+f(p_8) [WBF]
\nonumber \\
&2291 &  f(p_1)+f(p_2) \to W^-(e^-(p_3),\bar{\nu}_e(p_4)))W^-(\mu^-(p_5),\bar{\nu}_\mu(p_6))+f(p_7)+f(p_8) [strong]
\nonumber
\end{eqnarray}