\midheading{Direct $\gamma$ + heavy flavour production, processes 283--284}
\label{subsec:heavyfl}

These processes represent the production a real photon with a $b$
quark or a $c$ quark Since this process includes a real photon, the
cross section diverges when the photon is very soft or in the
direction of the beam.  Thus in order to produce sensible results, the
input file must supply values for both {\tt gammptmin} and {\tt
gammrapmax}. This will ensure that the cross section is
well-defined.

The calculation of process {\tt 283}--{\tt 284} is only available at leading order.