CERN's LHC resumes experiments at record-breaking energy

The Large Hadron Collider (LHC) resumed smashing particles together at unprecedented energytoday, churning out data for the first time in more than two years that scientists hope might help crack the mystery of "dark matter."

The LHC, a 27 km (17 mile) underground complex near Geneva, will smash protons at 13 tera-electron-volts (TeV), almost twice the energy achieved in an initial three-year run that began in 2010. This proved the existence of the elusive Higgs boson particle, a discovery that produced two Nobel prizes in 2013.

Nobody knows quite what the LHC might reveal with its new particle collisions mini-versions of the Big Bang primordial blast that brought the universe into being 13.8 billion years ago but scientists hope it will produce evidence of what has been dubbed "new physics."

A spokesperson for CERN's ATLAS experiment, which is one of the two general-purpose detectors at the LHC, said the restarting of the accelerator was a huge step forward for the science.

'A step forward in sensitivity'

"It means that we can probe to higher energies to produce higher mass particles and also to shorter distances than we'd been able to before. So we're taking a step forward in the sensitivity to possible new physics,"Dave Charlton said.

The LHC beam is formed of many bunches of particles, each measuring only a few centimetres long and a millimetre wide, smaller than the size of Spain on a one euro coin.

Its experiments aim to probedark matter, thought to make up some 96 per cent of the stuff of the universe whilst being totally invisible, and super-symmetry, or SUSY, under which all visible particles have unseen counterparts.

Although data has already been collected, since the LHC was turned on again in April, Wednesday marked the beginning of the second round of research.

"We have already taken data while the machine was tuning up the beams, but this is really the time when we start the physics program,"said Tiziano Camporesi, spokesperson for the CMS experiment.

If there is a particle missing from current knowledge of the building blocks of the universe, CERN scientists hope that it might be spotted, even fleetingly, in the debris of the billions of collisions, just as the Higgs boson was.

The collider underwent a $150 million upgrade after its first run, which produced results that helped confirm the existence of an elusive subatomic particle, the Higgs boson.

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