The Large Hadron Collider

You would have had to work very hard last week not to have heard that the Large Hadron Collider, the world’s most powerful particle accelerator, has just started operating on the Swiss-Franco border.

Superlatives abound in any discussion of the LHC. It’s the largest machine in the world, 27 kilometres in circumference, 100 metres underground. Its 9,300 magnets, cooled to -271.1 C, colder than outer space, contain enough superconducting filaments to stretch to the sun and back five times over. Thousands of scientists from dozens of countries are involved…including physicists from the University of Regina.

Which is why last Wednesday I was at the U. of R. for a teleconference linking media and physicists here with physicists in Switzerland, including Kamal Benslama, the U. of R. professor heading up the university team involved in the ATLAS project, the (here come those superlatives again) “largest experiment in the history of the physical sciences.”

The LHC will accelerate two beams of protons in opposite directions through its giant circular tunnel, then smash them together with such force that, on sub-microscopic scale, they will briefly recreate conditions last seen one 10-billionth of a second after the Big Bang, when the temperature was a million billion (that a one with 15 zeroes after it) degrees C.

When particles are smashed together, they break apart into a variety of what Benslama calls “physics objects.” By examining these “physics objects,” scientists learn more about the basic workings of the universe. To examine them, you need specialized detectors, and at the LHC, there are four–including ATLAS , the largest of the lot at 46 metres long, 25 metres high, and 25 metres wide.

The U. of R.’s team has been developing software used to monitor parts of the ATLAS detector and analyze the collision results.

It’s natural to ask, when one is looking at a $9.5 billion machine that took more than a decade to build, “What’s it good for?”
According to Manuella Vincter, a Carleton University professor who is also involved with the ATLAS project, the goals of the project fall into three categories.

First, there’s “bread-and-butter physics,” stuff we already know is there but that the LHC will be able to analyze with greater precision than ever before. “If you see any deviations from the model, it may be an indication of new physics,” she says.

Second, there’s “frontier physics,” things for which there may be indirect evidence and a really good theory, but no proof. “A theory is no good until you can actually prove it,” says Vincter. The best-known example of this is the theorized-but-not-yet-seen Higgs boson, the particle that is thought to give other particles mass.

Finally, there’s “blue-sky physics,” theories for which there is as yet no evidence. “Of every 99 there may be one that will pan out and the other 98 won’t,” Vincter says, but notes, “In all of the major colliders, we’ve tended to always find something really new and interesting.” Evidence of other dimensions? The existence of mini-black holes? No one knows, and that’s what’s exciting.

The LHC is very much a tool for basic research, but that doesn’t mean there’ll be no practical benefits. After all, research a hundred years ago into the electron had no practical purpose at the time, but without it, we’d have no electronics.

A more intangible but still important benefit lies in the personal and professional links forged among the thousands of collaborators on the project. They may all be working on different experiments, but they’re all part of the LHC team as a whole.

Which is why the successful circulation of a proton beam around the LHC last week was such an emotional moment. As Vincter recalls, “we were all pretty cool, relaxed, joking, then when the beam went through, you could not believe the screaming, the cheering, the whistling that went on for minutes and minutes. People, including myself, were crying.”

According to Kamal, “It was very, very, emotional. I can’t describe this feeling (but it) will stick in my brain forever.” He adds, “It’s really very important to understand this beautiful universe where we are living and how everything comes together.”

I couldn’t agree more.

Permanent link to this article: https://edwardwillett.com/2008/09/the-large-hadron-collider/

1 comment

    • Rick LeBlanc on September 15, 2008 at 7:03 pm
    • Reply

    A lot of puzzle pieces will come together if Atlas tracks down the Higgs boson. I can’t wait until we get graphical evidence showing different particles and their trajectories. Although postulated as a single particle, there could be further discovery if we get more.

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