Thanks a lot for this partial report. You look to be on the right tracks to finalise the episode, and I am really happy. I don't have much to write, but let me point out two things.

1] The plot you finally obtained, at the end, looks OK to me. As a simple suggestion, you could maybe reduce the maximum value of the X axis.

Each sub processes are unique with its corresponding initial and final state. The different Feynman diagrams which accounts the quarks that make up the protons that collided in the simulation.

2] The above answer to the assignment is the correct one. @eniolw: this should answer the question you raised in your own report :)

Cheers!