\midheading{$W+b{\bar b}+$~jet production ($m_b=0$), processes 24,29}
\label{subsec:wbbjetmassless}

These processes represent the production of a $W$ boson which subsequently
decays leptonically, in association with a $b{\bar b}$ pair and an
additional jet. The effect of the bottom quark mass is neglected throughout
and the calculation may be performed at LO only. The corresponding LO processes
with a mass for the $b$-quark are given given in {\tt nproc=431,436} and should be used
in preference to these processes.

When {\tt removebr} is true, the $W$ boson does not decay.