Meet the scientists!

One thing about physics that I think it’s good to learn at a young age is that whatever you think you know about a particular model, theory or process, it is often only true in a certain energy regime.  For example, Newtonian mechanics is true until things start moving at extremely high speeds or in very strong gravitational fields; gasses don’t behave so much like ideal gasses (non-interacting molecules) at high pressures; materials can behave quite differently on the atomic scale compared to their large-scale structures.

In particle physics there is a model, called the Standard Model, which we know to be pretty-much accurate up-to a particular energy (called the electroweak scale), just like we know Newtonian physics is accurate as long as you don’t move too fast and just as gasses behave like ideal gasses as long as the pressure isn’t too high.  There are some very good reasons why, at the energies the LHC is colliding protons at, we expect to see some new interactions that are not in the Standard Model we have observed up until this time.

Proton collisions tend to be quite messy affairs.  The proton is a kind-of bag full of many quarks and gluons, which interact via the strong force of QCD.  Generally what happens in a proton collision is you get a very large number of particles at (for the LHC) quite low energies, which go all over the place in the detector.  In amongst that, a very small fraction of the time there may be some higher energy particle(s) emitted that might be an indication of some new physics.  So it’s actually very important to have a good model of what a bog-standard proton collision looks like so that if something new happens you can be sure it isn’t just some miss-modelling of the already-known processes.  

In my spare time (!) I try to make photographs.  I think a nice project for a school would be to try and send a camera up to the stratosphere using a weather balloon.  Maybe this is a bit overly ambitious, but it has been done before for a similar amount of money…