March 5, 2015
Researchers looking to ‘break physics’ with LHC Run Two
Researchers at the Large Hadron Collider (LHC) at CERN in Switzerland have found through their experiments that theories surrounding particle physics have held up well so far – and that’s the problem.Just days away from restarting the LHC after a two-year break, CERN scientists are now saying that they want to use the newly-upgraded LHC to ‘break’ their robust theories.
"We have a fantastic model - that we hate," Steven Goldfarb, a physicist and software developer on CERN’s Atlas team, joked to BBC News. "It has stood up to precision measurements for 50 years. We get more and more precise, and it stands up and stands up. But we hate it, because it doesn't explain the universe."
Ready for the Run two
In addition to trying to change everything we know about particle physics, CERN scientists prepping for Run Two are also going to be on the lookout for new particles and other discoveries, including dark matter and anti-matter.
Run Two is slated to start in mid-March and will kick off with two beams of protons shooting around the LHC’s nearly 17 mile circumference in both directions. If all goes well with this initial two-month test phase, the LHC team will set the proton beam up so that they collide into each other.
While preparations for Run Two are currently taking place underground, all staff will be at ground level when the real experiments kick off.
"We're recreating temperatures that were last seen billionths of a second after the Big Bang," said Tara Shears, a particle physics professor from the University of Liverpool. "When you get to this hot temperature, matter dissociates into atoms, and atoms into nuclei and electrons.”
"Everything unravels to its constituents. And those constituents are what we study in particle physics,” Shears added.
After finding evidence of the Higgs boson, also known as the final unseen component the Standard Model, in 2012 – the CERN team said the so-called “God particle” will be scrutinized even more in Run Two.
"And although it looks like the Higgs boson that we expect from our theory, there's still a chance that it might have partners that would then tell us that we're not looking at our normal theory at all,” Shears said. “We're looking at something deeper and more exotic."
The team said they are also looking for signs of the highly-mysterious dark matter, which has never been seen, but is thought to make up about one-quarter of the mass in the Universe. One sign of dark matter would be “missing” energy after a collision that the scientists cannot account for.
"When you see a lot of missing momentum - more than is predicted in standard model - then you may have found a candidate for dark matter," Goldfarb said.
Then there's the matter of anti-matter
In addition to dark matter, CERN researchers are also looking for signs of anti-matter. Well known to science fiction fans, anti-matter is believed to have been generated in the Big Band and comprise 50 percent of matter in the Universe.
When a particle of anti-matter and a particle of matter collide, they "annihilate" each other and scientists argue that a lot of this annihilation took place – with only the scraps left behind. Yet, only scraps of matter have been observed so far.
"You just don't get anti-matter in the universe," Shears said. "You get it in sci-fi and you get it when things decay radioactively, but there are no good deposits of it around."
In general, CERN researchers said they’re excited to get Run Two going and begin a new journey of scientific exploration.
"It's like you've put a ship in the harbour and replaced every single plank," said Andre David, from the LHC’s CMS experiment. "It's not the same ship. It's a whole new ship and it's going on a new adventure."