The world’s most powerful particle collider is poised to roar once again into action after a two-year hiatus. At the end of March, the Large Hadron Collider (LHC) at CERN, Europe’s particle-physics lab near Geneva, Switzerland, will start smashing particles together at a faster rate and with higher energies than ever before. “We’re standing on the threshold of a completely new view of the Universe,” says Tara Shears, a particle physicist at the University of Liverpool, UK.

Credit: Nik Spencer/Nature

The first run began in earnest in November 2009 and ended in February 2013. The LHC collided particles — mainly protons but also heavier particles such as lead ions — at high enough energies to discover the Higgs boson in 2012, which garnered those who predicted the subatomic particle a Nobel prize.

Credit: Nik Spencer/Nature

In the next run, set to last three years, energies will rise to an eventual 14 teraelectronvolts (TeV; see ‘Hardware rebooted’). One hope is that higher energies will produce evidence for supersymmetry, an elegant theory that could extend the standard model of particle physics (see ‘Desperately seeking SUSY’).They could also shake out particles of dark matter, the invisible substance that is thought to make up 85% of the matter in the Universe (see ‘Decays decoded’).

Credit: Nik Spencer/Nature

More collisions will enable more-precise study of the Higgs’ nature (see ‘The Higgs factory’) and will provide clarity on anomalies hinted at in run 1 (see ‘Known unknowns’).

Credit: Nik Spencer/Nature

“In the first run we had a very strong theoretical steer to look for the Higgs boson,” says Shears. “This time we don’t have any signposts that are quite so clear.”

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Credit: Nik Spencer/Nature