by Robin Ann Smith
Buried 300 feet beneath the Franco-Swiss border in a 17-mile circular tunnel, the world’s biggest scientific instrument is revving back to life after a two-year overhaul.
Duke researchers are ready here in Durham and at the CERN physics laboratory near Geneva as the Large Hadron Collider gears up for its second three-year run.
By mid-summer, the largest and most powerful particle accelerator in the world will use its superconducting magnets to send beams of protons — invisible particles in the center of every atom — hurtling around the giant circular track at nearly the speed of light.
The reboot will ramp up to almost twice the energy of its first run, smashing protons together with a collision energy of 13 trillion electron volts.
One trillion electron volts is roughly the energy of a flying mosquito. While this isn’t much for a mosquito, it’s a huge amount of energy for something as tiny as a proton, which packs that energy into a space a million million times smaller than a mosquito.
By sifting through the debris that results from these collisions, researchers hope to figure out what particles may have existed in the first trillionths of a second after the “Big Bang” of the early Universe.
For the Duke scientists who have been involved in analyzing the data from the LHC’s first run from 2010 to 2013 — millions of gigabytes of data a year — the work never stopped.
That includes people like physics graduate student David Bjergaard, who studies an elusive, short-lived particle charmingly named the charm quark.
Bjergaard and other Duke scientists will be on-site this summer to continue their experiments at ATLAS, one of the four massive detectors that record the collisions.
The highlight of the LHC’s first run was the end of the 50-year hunt for a particle called the Higgs boson, the missing piece in a theory called the Standard Model of particle physics.
Now researchers are hoping to make more Higgs particles and study them more closely. But they’re also on the lookout for surprises.
“Maybe we’ll see something completely unexpected that doesn’t fit into any of our current models,” said Duke physics professor Mark Kruse, who from 2007 to 2009 led one of the teams that searched for the Higgs boson at Fermilab near Chicago.
“I am excited about the possibility,” said Duke graduate student Chen Zhou, who has been working with Kruse on a way to search for so-called ”new physics” by looking for events that show up in the ATLAS detector as a high-energy electron together with a similar but heavier particle called a muon.
If new particles are lurking just around the corner, then they should be detected fairly quickly, Kruse said.
Duke student researcher Elena Villhauer will be scouring the data for hints of “quantum” black holes. These aren’t the black holes of space horror films — collapsed stars from which nothing, not even light, can escape — but harmless black holes that are smaller than a proton and evaporate instantly. If found, they would support the existence of extra dimensions in space beyond the three that we see.
“It’s science fiction possibly coming to life,” said Villhauer, who has been based at CERN since July 2014.
Other Duke students will be looking for the invisible substance called “dark matter,” which makes up most of the mass of the universe but has never been produced in the lab. “We know that dark matter exists. The only question is, can we produce it and detect it at the Large Hadron Collider? It could manifest itself in ways that we might not expect,” Kruse said.
The Duke researchers are among 10,000 scientists from 113 countries who collaborate on experiments at Large Hadron Collider.
For Lei Li, a Duke graduate student in physics who moved to CERN last year, the best part about living on-site is the opportunity to mingle with world experts in her field, face-to-face, on a daily basis.
Before, if she wanted to talk to someone working on the supercollider she had to connect remotely online, and deal with a six-hour time difference.
“[Now] If I come across a problem, I just invite an expert to grab a coffee,” she said.