Conceptually, how does one calculate hadron scattering processes from the strong force, if one has the amplitudes for 2x2 scattering of quarks and gluons? For example, the strong force between a proton and a proton, both made from uud quarks - is this therefore a 6x6 scattering? I went through a lot of tedious math, manipulating a bunch of twistors, to get the amplitude for 2x2 elastic scattering of: 4 quarks; 2 quarks and 2 gluons; and 4 gluons; but the book stops there and doesn't talk about how to calculate hadron scattering processes. I don't even know why I calculated 4 gluon scattering and 2 quarks 2 gluons scattering - are there free gluons inside the hadrons? How many gluons are there inside? So a proton is really made of uud quarks and more than 1 gluon? So proton-proton scattering by the strong force is greater than 6x6 if you include the gluons? The energy scale in order to apply perturbation theory to strong processes is said to be the mass of the Z-boson. Is this the reason that QED is sometimes renormalized at the Z-boson mass, so that one can compare the effects of the strong force to the electromagnetic? Also twistors seem kind of tedious. Are QCD calculations without using the twistor method easier?