### Summerschool in Zakopane

I went to a really nice summer school on high energy physics in Zakopane (Cracow School of Theoretical Physics 2014). Zakopane is situated in the Tatra mountains of southern Poland, a place I will seriously consider returning to for holliday. Look at the beautiful scenery from the mountain just outside the school!
Luckily the school was not mostly about the view -- it was about understanding collisions of protons at very high energy and collisions of heavy atomic nuclei. When I say very high energy, that is a statement with some ambiguity. Since protons are constituent objects, consisting of quarks and gluons, you don't really collide protons; you collide the constituents. This means that two different energies (or 'scales' as we would say) enters the problem. We have the full proton energy, and then the fraction of proton energy going into the collision of constituents, the so-called 'hard collision'. To enable a calculation of the hard collision, one needs to have some kind of model for how the proton is populated with quarks and gluons. It turns out that this is very dependent on the fraction of energy taken out for the hard collision. When this fraction goes very small, the amount of gluons rise dramatically, and the proton gets 'overpopulated' with gluons. A lot of different theories about this overpopulation exists, but a particularly popular variant of this predicts that the proton will simply saturate with gluons at one point. I am working with such a model myself, and so far we have not experimentally seen clear indications of such saturation effects. But as the energy of the experiment rises, more and more interesting collisions for observing saturation effects will be made, and so we are very interested in understanding our models better before the LHC starts making collisions again in 2015.
I made a presentation about my own work, which was fairly well recieved. If you want to look at the slides, you can find them here.
I also had time to play a little bit of music. At the conference dinner a very nice group of Polish folk singers played the traditionals of the region, and I got to be invited on stage to play a couple of songs with them on a borrowed guitar. Above is a (bit grainy) picture of the folk singer group in the traditional outfit of the region.