Atom smasher ramps up chase for 'God particle'
Particle accelerator reaches new, mind-blowing heights.
Thu, Oct 21, 2010 at 10:34 AM
The world's largest atom smasher has been upping its game ever since it opened in 2008. Just last week it reached a new milestone — the particle accelerator is now smashing unprecedented numbers of protons into each other during each collision.
The Large Hadron Collider at the European Organization for Nuclear Research (CERN) in Switzerland is the world's most state-of–the-art physics experiment. Scientists are crashing matter's building blocks together in the hopes of revealing even smaller building blocks, new undiscovered particles that make up our universe, including the theoretical "God particle," which is thought to give other particles mass.
The accelerator consists of a 17-mile-long (27 kilometers) ring buried underground where powerful magnets guide particles along the circle to pick up speed. At a few points along the loop the beams of particles intersect, and when two particles collide, they convert their enormous kinetic energy into new matter via Einstein's equation E=mc2.
100,000 million protons
The machine started out sending one bunch of protons at a time around the ring in each direction. Now it sends 256 bunches at once. Each of these clusters now contains 100,000 million protons (that's 10^11 protons.)
While that's an improvement, it's only part of the ultimate goal.
"We've got a long way to go," said Mike Lamont, LHC's head of operations. "For this year, we hope to get up to 400 bunches."
The team also plans to boost the collision rate of particles in other ways.
"At the interaction point where bunches pass through each other, we can work on the number of protons in a bunch, the number of bunches, and also the actual size of the beam at that interaction point," Lamont told LiveScience. "At the moment it's focused down to 60 microns – about diameter of human hair. What we can do is reduce that size even more."
The smaller the beam is squashed, the less space the particles will have to move around, and the higher the chances they will run into each other at the collision point.
The more head-on crashes the accelerator creates, the better the chances of one of these events producing something unprecedented – like the Higgs boson, for example.
The ‘God particle’
The Higgs, also known mystically as the "God particle," is a theoretical particle that gives other particles their mass. According to the concept, Higgs particles create a field throughout the universe, and when other particles pass through the field, they interact with it and acquire mass.
If LHC can create one of these Higgs particles, it would be a major coup for physicists and would go a long way toward explaining the fundamental nature of matter.
The particle accelerator is probably not producing enough collisions yet to find the Higgs, but even at its current levels, scientific experiments are ongoing.
"All the experiments are working very well – we've certainly given them a good data set this year," Lamont said. "But to find the really interesting stuff like Higgs or supersymmetry, they're going to need a lot more data."
Supersymmetry – another big goal for LHC – is the theory that every particle has a partner particle that has similar properties but a different spin. (The supersymmetric partner of a quark would be a squark, and the partner of the electron is called the selectron – apparently physicists love silly names).
Many of these particles would be very massive and very difficult to detect, but the lightest of them could be created during the crashes in LHC, scientists predict.
Full throttle ahead
To get to the point where Higgs and supersymmetric particles might be discovered, the LHC will likely have to function at peak capacity.
"For us it really is a matter of increasing the amount of data we deliver to the experiments – they just need more, more, more," Lamont said. "They're looking for a very small needle in very large haystack."
The accelerator was designed to run at energy levels of 7 teraelectron volts (TeV), but right now it is only going at half that power – 3.5 TeV.
That's because the cables connecting the superconducting magnets that propel the particles around the LHC ring were built with a flaw that was revealed shortly after the machine was first turned on. In order to ramp up the power, LHC workers will have to shut down the accelerator and make significant repairs to the magnet connectors.
Once that's done and LHC is running at peak design parameters, particles will be colliding at mind-blowing rates.
"Our collision rate eventually will be enormous," Lamont said. "When we get to design, we're talking 600 million events per second."
For comparison, about 6 million particles currently collide per second.
That's still not too shabby. The machine is already more sensitive in some channels than the world's second-largest atom smasher, Fermilab's Tevatron in Batavia, Ill.
This article was reprinted with permission from LiveScience.
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