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The World's Most Powerful Particle Accelerator Is Going After Dark Matter

The Large Hadron Collider will be smashing particles again by the summer.
March 12, 2015, 4:15pm

​It's always hard to top a blockbuster first season that left off with a killer surprise ending, but the team at CERN's Large Hadron Collider hopes season two will be even wilder than the first.

The world's most powerful particle accelerator wrapped up its first season (what CERN calls the period when the LHC is active) in 2012 with the discovery of the Higgs ​boson—the "God" particle that helps explain how particles gain mass—and it may seem hard to top that. But after taking some time to do a complete overhaul of the LHC, CERN is set to fire it back up this year for another three-year season, running at nearly double the energy it had in its first season. They've also replaced many of the high-powered magnets that drive the accelerator, have reinforced all 10,000 electrical connections, and will be using narrower beams.


These improvements will not only allow the researchers to gain more insight on the Higgs boson (and possibly find other, similar particles) but it will also help them in their quest for answers to some even bigger questions about the universe, like what the hell dark matter is.

"What is the dark matter we see out there in the universe?" asked David Charlton, the scientific lead on the ATLAS experiment at the LHC, during a press conference this morning. "We know it has to be there, can we create it and study it in the laboratory?"

The team cautioned about getting too excited. Running the LHC with more energy (the collision energy will be 13 TeV compared to 8 TeV in 2012) opens the door to producing a new state of matter never before detected (remember E = mc2), they have no idea about the probability of it being enough energy to detect something like a dark matter particle.

"It's in the hands of nature," explained Rolf Heuer, the general director of CERN, noting it could happen in the next year or they may never find it. "I have a dream. I want to see the first light in the dark universe. If I see that, then nature is kind to me."

But there are other big questions they're tackling, like finding a new system to replace the Standard Model of Physics, a kind of incomplete place​holder framework for understanding the universe. Finding particles similar to Higgs boson could help physicists develop a new system, but so could discovering that the Higgs is all alone. Heuer likened it to a child: an only child behaves and reacts differently than a kid who grew up in a family of 10 children, so searching for other Higgs-like particles will explain a lot.


"It is high time we find a crack in the Standard Model because about 95 percent of the universe is still unknown to us. So there must be something beyond this model," Heuer said.

The next season will also focus on such lofty questions as the origin of matter, the relationship of matter and antimatter, and will look for evidence of Supersymmetry (a theoretical alternative to the Standard Model). They'll also be collecting more than double the amount of data, possible discoveries for years to come.

The process to fire the accelerator up again has begun, but it will take a few more months before everything is ready to start smashing particles again. The team is hoping to have the first collisions by the end of May.

"It's not like a phone or a fridge you can turn on or off," Frédérick Bordry, the director of accelerators at CERN, said. "I cannot say when we will pass from off to on, but we are preparing it at this time. We put a beam in last week, but it's a long process."

CERN fired a particle beam through the LHC last weekend to debug any lingering problems—they found a magnet that had the wrong polarity, for example. It's just one of the many steps required before they start collisions again without risk of damaging the machine and causing delays.

But once things are up and running, the LHC will have a good three years of collisions providing data to unlock mysteries of the universe in the only machine on the planet capable of detecting them. LHC will then power down for another year or two of maintenance before entering season three, and will continue in this pattern for the next 20 years.

Of course, there will be plenty more questions than answers by the time this season wraps up, but luckily we've got some of the smartest, and most stubborn, human beings looking for answers on our behalf.

"Experimental particle physicists never give up," Heuer said. "We don't stop."