Cern's Large Hadron Collider restarts with sights set on dark matter | Science | The Guardian
The world’s largest and most powerful atom smasher has been restarted after an upgrade that could see it making scientific history for a second time.
Shortly after 8.30am on Sunday UK time, scientists sent two beams of high-energy particles racing through 16.7 miles of the Large Hadron Collider’s circular underground tunnels.
Cern confirmed that the anti-clockwise beam, B2, had completed a circuit of the machine, passing through all four detectors, at 9.41am.
Confirmation that the restart had been successfully carried out came at 11.27am, as the second, clockwise, beam completed a full circuit of the Large Hadron Collider (LHC).
Cern’s director general, Prof Rolf-Dieter Heuer, who was in the control room, said: “The beam went smoothly through the whole machine. It’s fantastic to see it going so well after two years and such a major overhaul of the LHC. I am delighted and so is everyone in the Cern control centre - as are, I’m sure, colleagues across the high-energy physics community.”
Two years ago the team operating the £3.74bn machine under the Swiss-French border astounded the world with the discovery of the Higgs boson, an elementary particle that gives other particles mass.
Now they have their sights set on an even more exotic trophy: dark matter, the invisible, undetectable material that makes up 84% of matter in the universe and binds galaxies together yet whose nature is unknown.