By BlueShift | 2026-07-16

The world's most powerful particle accelerator has halted operations for four years as it begins renovations that will boost its collision capacity and potential for understanding dark matter, one of the universe's greatest mysteries.

The Large Hadron Collider (LHC) of the European Organization for Nuclear Research (CERN) is a 27km proton-smashing circular tunnel, about 100 meters below the French-Swiss border area.

It was used to prove the existence of the Higgs boson, dubbed "the God particle," which offers physical proof of an invisible, universe-wide energy field.

Until work halted at the end of June, superconducting magnets and accelerating structures inside the tunnel propelled particles to extreme energies and then smashed them together at phenomenal speeds, per AFP.

Upgrades aimed to increase the precision and intensity of particle collisions are now under way, with the resulting High Luminosity LHC (HL-LHC) slated to begin operations in June 2030.

The upgrade is no minor facelift, per Science News.

Accelerator components in 1.2km of the tunnel, and new superconducting magnets that are capable of further concentrating the particle beams, are being installed to increase the number of collisions.

The completed HL-LHC will have up to 10 times the luminosity -- the total number of collisions produced over a given period -- of the LHC, enabling scientists to collect significantly more data.

Once operational, between 140 and 200 collisions will occur each time two packets of particles meet inside detectors in the tunnel, up from 60.

The $1.5 billion upgrade is being funded via CERN membership fees, with in-kind contributions from the United States, Japan, Canada and China, among others.

Deepening knowledge of the universe

Scientists believe that ordinary matter accounts for just 5% of the universe. The rest is believed to consist of dark matter (27%) and dark energy (68%) -- two invisible components they have yet to detect or directly observe.

Once the upgrade is completed, CERN hopes to dramatically expand its understanding of how the "God particle" works, with the HL-LHC expected to produce around 380 million Higgs bosons over its lifetime.

This is compared to 55 million found since LHC operations began in 2008.

The lab hopes to produce two Higgs bosons simultaneously and see them interact, said research physicist Nedaa-Alexandra Asbah of CERN's ATLAS experiment, which helped discover the Higgs Boson using the LHC.

This "may provide clues about how our Universe evolved shortly after the Big Bang," she said.

The HL-HLC expected to have run its course by around 2040. In May, the CERN council updated the European Strategy for Particle Physics, designating the the Future Circular Collider (FCC) as its preferred successor.

This officially elevated the concept to a formal plan, but stops short of a commitment to construction. Pending approval, work on the initial stage, the FCC electron-positron machine (FCC-ee), would begin in 2030.

The FCC-ee would start operations in 2047, after the HL-LHC closes down, and run for about 15 years, with a second machine, the FCC-hh beginning operation in the 2070s and running for around 25 years, according to CERN.

FCC-hh machine, for hadron-hadron collisions, would smash protons together at high energy with the aim of creating new particles.

LHC's groundbreaking discoveries

Results from the LHC have spurred physicists to think big, University of Chicago particle physicist Young-Kee Kim told ScienceInsider.

They initially hoped the LHC would find not just the Higgs, but other new particles as well, she said, which meant the LHC’s successor could be a smaller, straight-shot linear collider that would study those particles in detail.

But because the LHC has produced only the Higgs, enthusiasm shifted from a linear collider to a scheme that could eventually lead to a much larger proton collider, which might deliver the hoped-for discoveries.

In March, the LHC discovered a new particle, the 80th it has identified so far.

Scientists hope the "Xi-cc-plus" particle -- which is similar to a proton but four times heavier -- will reveal more about the strange behavior of quantum mechanics, AFP reported.

All the matter around us -- including the protons and neutrons that make up the nucleus of atoms -- are made of baryons. These common particles are composed of three quarks, which are fundamental building blocks of matter.

The discovery was "only the second time a baryon with two heavy quarks has been observed," said LHC beauty experiment spokesman Vincenzo Vagnoni.

It was also "the first new particle identified after the upgrades to the LHCb detector that were completed in 2023," he said in a statement.

"The result will help theorists test models of quantum chromodynamics, the theory of the strong force that binds quarks into not only conventional baryons and mesons but also more exotic hadrons such as tetraquarks and pentaquarks."

While the LHC upgrades are under way, scientists will continue to process and analyze the previous collision data it collected, hoping to make new discoveries.