Large Hadron Collider to restart and hunt for a fifth force of nature

The Large Hadron Collider (LHC) will restart on Friday after a three-year hiatus and is expected to resolve a scientific cliffhanger on whether a mysterious anomaly could point to the existence of a fifth fundamental force of nature.

The tantalising findings reported last year have reignited hopes that the 20 mile-long collider could deliver a second blockbuster discovery, more than a decade after the Higgs boson.

However, data collected in the LHCb experiment, one of four huge particle detectors at Cern in Switzerland, appeared to show particles behaving in a way that could not be explained by the standard model.

Before the LHC was switched off for an upgrade in 2018, the team collected enough data to suggest the odds were roughly a thousand to one of the result happening by chance. But the gold standard for particle physics is a more stringent one in 3.5m level of confidence, meaning more data is needed before a discovery can be declared. There is also a lingering possibility that some unknown experimental glitch could explain the findings.

In the past year, anticipation has been heightened by further intriguing hints of physics beyond the standard model seen in other experiments, including recent unexplained findings from Fermilab in the US.

The third run, expected to last until 2026, follows an upgrade that has included the installation of additional powerful magnets designed to squeeze the protons inside the collider into finer, denser beams. This will increase the collision rate of particles inside the accelerator, meaning scientists will be able to observe rarer events with greater precision.