Content
The LHC is the biggest and most powerful particle accelerator in the world. It was built to enter unknown terrain beyond the standard model. The reason is that there are still gaps in that same standard model, even with its great success in explaining the building blocks and forces of our universe and its strong experimental confirmation. The experiments at the LHC will provide answers to some open questions like how particles get their masses or why the universe has more matter than antimatter.
In order to get those answers bunches of protons are shot at bunches of protons. But which objects interact during a proton-proton-collision? These are the components of the protons (gluons and/or quarks). You can get the picture of what is going on during a collision from the graphic below:
During the initial phase of LHC operations physicists keep their eyes on every elementary particle of the standard model. All of them were successfully rediscovered within a few weeks only, e.g. bounded systems of quarks and antiquarks (Charmonium and Bottonium, originally discovered in 1974 and 1977), unbounded heavy Top Quarks (first discovered in 1995) and W and Z Bosons (discovered at CERN in 1983). In order to reliably discover new particles in proton-proton collisions, it is necessary to assign known particles to LHC events unambigously. This not only confirms previous results but also shows what already-known physics looks like in the new environment of the LHC detectors.
Thus the focus is on particles like the W-boson. Let's elaborate on what this exchange particle of the weak interaction is telling us about itself and how it appears in the ATLAS detector.