And now for another smash hit…

The chance of finding new physics and particles when CERN’s huge underground device, the Large Hadron Collider, roars back to life this Spring is rated strong by many science-watchers – but CERN scientists are staying sober.

“The machine is coming out of a long sleep after undergoing an important surgical operation,” said Frédérick Bordry, CERN’s Director for accelerators and technology. Over the last 24 months, the giant atom-smasher has been set on snooze; in March, it re-awakens.

After millions of collective hours spent doing maintenance work on the collider, the LHC will return with a refit and a re-tuning. The LHC’s first phase of operations lasted from 2008 - 2012. In the new phase, the LHC will attain collision energies at twice the force that enabled discovery of the Higgs boson in 2012.

Expectations for further advances are high, but inside the laboratories and tunnels in Geneva, there are notes of caution. “It’s a new regime, we’ve never been here before, so we don’t have concrete expectations,” said Paul Collier, CERN’s Head of Beams. However, he did say some early discoveries can be expected around May or June this year

As the man with his finger on the button, Collier’s job is to manage the €10 billion accelerator complex as it propels protons, in two beams steered by magnets, to near light speed.  “The more bang you’ve got, the more chance of finding exotic particles,” Collier explained.

However, he is not overly concerned with endless physics discussions – “my job ends when the beams hit each other,” he said.

Finding the last Russian doll

The question hanging over the revived LHC is if it will allow CERN researchers to produce a second discovery about the nature of matter to rank alongside the breakthrough discovery of the Higgs boson. The scope is certainly there, said Collier, with 95 per cent of the universe still unexplained.

“Finding the Higgs boson wasn’t really a surprise,” said Gian Giudice, one of CERN’s theoretical physicists. “This time round though, it’s unexplored territory.”

The work of the next-generation collider is summed up by Giudice in a neat analogy. “We’ve seen nature is made up of layers, like a Russian doll. How does it end? How far away are we from finding the final doll?” said Giudice.

In principle, the LHC might be able to provide evidence to substantiate the multiverse theory, which states that we do not live in a stand-alone universe, but inhabit a small pocket of an infinite number of universes. “A beautiful idea, one that’s extremely deep, [the theory] implies we won’t find the last Russian doll,” said Giudice.

Dark matter

There will also be attempts to pin down dark matter, so called because it does not emit light or any other kind of radiation.

It’s more than likely out there but no scientist has been able to put their fingers directly on it. Without having ever been observed, its existence is inferred, said Giudice. “We can measure its presence, its gravitational effects. But it doesn’t shine like matter does,” he said. No one is sure what it is made from. “It doesn’t have what we’d consider as normal matter: subatomic particles like protons, neutrons and electrons,” Guidice said.

Apart from trying to glimpse dark matter particles - a feat akin to searching for a needle in a haystack - according to Collier, the LHC’s job will be to artificially produce dark matter particles for CERN scientists to measure.

CERN scientists will also be hoping to detect dark energy. Even more elusive than dark matter, dark energy drives the expansion of the cosmos. “We don’t have many ideas on what that is,” said Collier.

Sweating the God particle

Scientists would also like to learn more about the Higgs boson. “We don’t have the full story,” said Giudice. “We suspect the Higgs boson is hiding something else; that it’s the first suspect to something deeper,” he said. “Perhaps we’ll find it’s not the most elementary thing on the planet,” he mused.

But just how likely are any new discoveries?  “You’ll have to ask the LHC, that’s why we built it,” Giudice said. “It’s very exciting in any case: we’re opening the door on another world.”