Europe’s Large Hadron Collider tests the bounds of physics – and budgets
Scientists look for technologies to push particles faster, better, and cheaper.
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The small number of affected electrons, and the one-instance nature of the experiment show this approach clearly is a work in progress, researchers say. Linear colliders require multiple shots of particles to build up enough collision statistics to yield a meaningful interpretation. Within two years, the research team expects to have a two-shot experiment ready to fire. If they can pull off a rapid-fire repeat, “then we’ve got something,” says Thomas Katsouleas, dean of Duke University’s Pratt School of Engineering and a member of the team working on the approach.Skip to next paragraph
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Other teams are using lasers, instead of an initial pulse of electrons, to set up the wake in the plasma. In 2006, a group a the Lawrence Berkeley National Laboratory and Oxford University reported kicking an electron beam to more than 1 billion electron volts over a distance of less than two inches.
But there may be hope yet for ensuring rings don’t fall out of fashion. Researchers also are exploring “muon colliders.” Muons are heavier cousins to electrons. With far more mass than an electron, muons can be used in circular accelerators, notes Harold Kirk, a physicist at Brookhaven National Laboratory in New York. They are still fundamental particles and so would yield the same clean hits that electrons provide. But they decay into other particles in 2.2 millionths of a second, he adds.
That sets up a significant challenge, he says, “to get the muons created, captured, collected, and accelerated” all within a muon’s lifetime. Einstein’s theory of special relativity, however, comes to the rescue. Once the muons are accelerated to nearly the speed of light, 2.2 microseconds from the particles’ perspective stretches out to many milliseconds as seen by a technician monitoring the particles. And that’s plenty of time to get the collision work done, he adds.
Last year at CERN, a team Mr. Kirk led put a prototype muon factory through its paces and showed that it could generate copious number of muons. The process also generated another type of particle physicists are keenly interested in – neutrinos. Thus a muon collider could pull double duty as a tool for neutrino physics, in addition to it high-energy-physics duties, Kirk says.
The next step, he adds, is to collect and cool the diffuse cloud of muons so that they can be focused and sent as a beam through an accelerator. The team is working on a concept to achieve that goal in an experiment in Britain slated for sometime in the next two years.
For more LHC coverage, check out:
As a massive atom smasher powers up, ‘Big Science’ moves away from the US
Could the Large Hadron Collider destroy Earth?
[Editor's Note: As a commenter pointed out, the original version of this story had Einstein's theory flipped around. The faster a muon travels, the longer it takes to decay from the technician's point of view.]