I'm looking for resources on the computation of (I think) very simple Feynman diagrams for QCD processes. The processes are q'qbar' -> qqbar and gg->qqbar (only at tree level, no loops involved) and my main problem is the computation of the colour factors.
I'm not interested in the absolute value of the cross-section, but in the angular distribution (in terms of cos theta). At least for the gg->qqbar process I think I need the correct factors though, to correctly add the diagrams.
I've already looked into the Quantum Field Theory book by Peskin, but there I only found the final cross-sections but not the calculation.