The studies are made with simulations of real events. The programs that simulate the physics at the collision are written at the theoretical department in Lund. There are also simulations of the detector as it will look during data taking and other programs that reconstruct the events from the electrical signals in the detector. The picture above shows a simulated event as it developes in the simulation of the detector. The proton beam enters from the left.
All particles origin from the same spot at the target where the collision took place.
The two pink tracks are electrons that, according to the analysis, origin from the decay of a heavy particle built up by a b-quark.