Simulated object AHH0000eub
by Whoandwhatitis moderator
This is a simulated object (denoted by the green/white "Simulation" tag beneath the image in the discussion page). This is pretty clearly an off-center vertex, which means that something collided or decayed and created a shower of charged particles. We know the particles are charged because the paths (lines) are shown. We also see a lot of energy (yellow boxes) in the electromagnetic and hadronic detectors in line with these particles.
The colors of the lines aren't especially significant except for the green of the two muons.
More information may be found in the FAQ.
I'd be glad to answer any other questions you have about this.