"We are exploring truly fundamental issues, and that's why this run is so exciting," physicist Paris Sphicas told AFP at Europe's physics lab, CERN, last week.
"Who knows what we will find," he added, with CERN saying preliminary results from the run could be available in the next few months.
Scientists had been gearing up to resume experiments at the LHC this week, but the plans were delayed after a weasel wandered onto a high-voltage electrical transformer last Friday, causing a short-circuit.
Late last year, before CERN shut down its Large Hadron Collider (LHC) for a technical break, two separate teams of scientists said they had discovered anomalies that could possibly hint at the existence of a mysterious new particle.
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The discovery of a new particle could prove the existence of extra space-time dimensions, or explain the enigma of dark matter, scientists say.
The LHC, housed in a 27-kilometre tunnel straddling the French-Swiss border, has shaken up physics before.
In 2012 it was used to prove the existence of the Higgs Boson -- the long-sought maker of mass -- by crashing high- energy proton beams at velocities near the speed of light.
The Higgs fits in with the so-called Standard Model -- the mainstream theory of all the fundamental particles that make up matter and the forces that govern them.
But the anomalies, or "bumps", seen in the data last December could indicate something completely new.
Going beyond the Standard Model would "mean that there is yet another unbelievable idea out there. Something that is totally unthinkable," Sphicas said.
The LHC, he said, could unveil whole new dimensions, help explain dark matter and dark energy, of which we have no understanding but which together make up 95 percent of the universe. The giant lab might also prove the exotic theory of supersymmetry, SUSY for short, which suggests the existence of a heavier "sibling" for every particle in the universe.