The LHC really became a collider just before Christmas. The collisions recorded back then were not at particularly high energy, but three experiments have now published results; my experiment, Atlas, being the latest, with the paper being accepted for publication only last week. Before storming onward, it is a good moment to see what these results actually tell us. The detectors (Alice, CMS and Atlas) are really just huge digital cameras designed to record what happens when protons smash together. The first thing you do with a new collider and detector is measure the particles produced in an “average” collision. Measuring average, typical events tells us various things. We know the proton is full of quarks, stuck together by the strong nuclear force. How it behaves at high energies is not very well known, and these measurements will help. They also help us understand backgrounds to rarer events, for example, those where a Higgs particle (which is thought to bestow mass on elementary particles) might be produced, and inform models of massive air-showers, which happen when cosmic rays hit the upper atmosphere. You can see in the Atlas paper that the models don’t fit the data quite right. The model builders are already tuning up to improve this.
more from Jon Butterworth at The Guardian here.