Hello, currently I work on 2->3 scattering process. So there exist five external momenta and in my case 5 different Feynman diagrams, for which I have already calculated the full matrix element. The matrix element is a function of various scalar products of the four-momenta. This scattering contains quarks. My next aim is to calculate the hadronic cross section from the matrix element. Can someone explain me how can I do this?