Friday, August 24, 2007

The Large Hadron Collider

There are several experiments going on at CERN, but the big one, the one everyone’s excited about, is the LHC. It’s still being built, but when it’s done it will be by far the largest accelerator ever made. We’re talking an order of magnitude more powerful than the runner-up, the Tevatron at Fermilab (just outside of Chicago).

But what is a collider? I’m so glad you asked. A collider is a big ring (actually a pair of rings, one right inside the other). Its job is to accelerate particles (in this case protons) in both directions. It gets them up to very close to the speed of light (about 99.9999997% of the speed of light) and then smashes them together in a head-on collision. This isn’t very healthy for the proton (the parts of it that aren’t annihilated instantly are shredded into several hundred pieces) but it turns out it’s a pretty good way to find new physics. We build huge detectors at the points on the ring where we’re colliding the particles and see what comes out.

Physically, the LHC is an enormous underground ring 27 km in circumference, which comes to about 5.3 miles in diameter. Seriously. It's 5.3 miles in diameter. That’s the distance from Townview to the CafĂ© Brazil on Central, and it’s all one giant machine. You could fit several small villages on the inside of this thing. And I know, because when I drive out to Point 5 on the circumference of the ring, I have to go through several small villages. So the thing is pretty big.


CERN is the European Organization for Nuclear Research, but I guess when you say it in French the acronym makes more sense. Actually, the acronym doesn’t make a whole lot of sense anyway, since nobody really does any nuclear research there. CERN is the world’s largest particle physics lab, and the particles we’re talking about are much, much smaller than nuclei. It turns out that in physics going down in size means going up in energy, so what I do is sometimes called high energy physics.
Aerial view of CERN. Off to the right is where I live. Just
out of the picture to the left is the only McDonalds in miles.

CERN itself lies on the border between Switzerland and France, which you would think makes for a lot of paperwork, but I guess not. I usually work at one of the sites in France, but sometimes I go over the main office in Meyrin, Switzerland. The transition is so smooth that sometimes you forget you’re passing between two countries. In total, about 8,000 physicists of all ranks work on CERN experiments, which is about half of all particle physicists in the world.

About Me

I’m a former TAG student, and I graduated in 2001. During my senior year I got Rebecca to let me take mechanics and E&M concurrently. (At the time she only offered mechanics, so you guys are lucky.) Anyway, after I left TAG I did my undergrad at Rice, where I majored in physics and math, which was a fairly equal mix of entertaining and agonizing. On graduating from Rice, I hopped clear across the country to the University of Wisconsin, because I wanted to work with a guy there named Wesley Smith. That seems to have worked out pretty well, because I spent the next couple of years finishing up my grad classes, and on June 4th he moved me out to CERN in Geneva, Switzerland, which is where I am at the moment. I’m currently doing research on something called supersymmetry, and in the next couple of years I’ll write and defend a dissertation, at which point I’ll get to be “Dr. Weinberg”.


Hello physics people! If you’re currently enrolled in Dr. Jensen’s physics class, then this blog is for you. My goal in writing this is to give you an impression of what physics is like out at the frontiers, and what it means to actually “work” in physics. So I’ll try to cover lots of stuff, but I’ll also post some physics puzzles here from time to time that relate to areas you wouldn’t normally run into, like relativity, quantum mechanics, quantum field theory, and particle phenomena. Maybe, secretly, you’re thinking about majoring in physics and you’d like to know what it’s like. If that’s not you, that’s cool; maybe you’ll find something in here to impress your friends and confound your enemies.
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