Experimental Excitement!
Well, this week is a big week, in some ways. The Large Hadron Collider has gone into a new phase! For a while, the experiment has turned aside from the task of searching for the origin of mass (the Higgs Particle, or whatever it is that mediates the generation of the masses of elementary particles – see earlier posts, and features like this, etc) and is turning to heavy ion collisions. Rather than studying processes in which only a few particles at a time are interacting at super-duper-uber-high energies, the experiment will instead collide together the nuclei of lead atoms, so that you get lots of particles colliding together and creating a messy “soup” of high energy stuff all together. The goal is to understand the constituent nuclear particles (quarks and gluons) working collectively at high temperature (and low to moderate density), instead of focusing on issues concerning individual fundamental particles. Today (starting late yesterday, actually) is an exciting day because it marks the first step on the journey to probe deeper into this physics. The ALICE experiment has started looking at these collisions. See top right for some screen-shots of the mess of particle tracks that are left after the soup flies apart. The trick is to analyze all these tracks from millions of such collisions to work out the properties of the soup.
As you perhaps know from reading this blog, while of course I’m interested in the behaviour of fundamental particles and the origin of mass, and so on and so forth, I’m very interested in this nuclear issue too. Some of the most interesting work that […] Click to continue reading this post
