Top News

The large hadron accelerator restarts to move the physics to the edge

Scientists overseeing Earth’s largest particle accelerator turned it on this weekend for the first time in three years to solve some of physics’ greatest mysteries.

The Large Hadron Collider (LHC), a powerful particle accelerator based at CERN near Geneva, Switzerland, restarted on Friday (April 22) after a three-year shutdown due to maintenance and upgrades. The reactivation kicked off what scientists call Run 3, the LHC’s third scientific run to conduct experiments by 2024.

“The machinery and equipment underwent major upgrades during the second long shutdown of the CERN Acceleration Complex,” said Mike Lamont, CERN’s Director of Accelerators and Technology, in a statement on Friday. “The LHC itself has undergone an extensive consolidation program and will now work with even higher energy and deliver significantly more data to the LHC’s upgraded experiments thanks to major improvements in the injector complex.” These experiments will build on the discoveries of the LHC during its run 1 (2009-2013) and run 2 (2015-2018).

Related: Large Hadron Collider explores state-of-the-art physics after 3 years of decommissioning

To reactivate it, the scientists fired a 16.7-mile (27-kilometer) LHC ring to inject two beams of protons in opposite directions at an energy level of 450 billion electron volts. This is just an appetizer for even higher energy levels, the LHC will operate once it reaches its target of a staggering 13.6 trillion electron volts for Run 3, the researchers said.

“These beams circulated during the injection energy and contained a relatively small number of protons. High-intensity, high-energy collisions are in a few months,” said Rhodri Jones, who heads the beam department at CERN. “But the first rays represent a successful restart of the accelerator after all the hard work of a long shutdown.”

The three-year shutdown of the LHC has allowed scientists to make substantial improvements to four key particle accelerator experiments. According to CERN, the ATLAS and CMS detectors themselves record more particle collisions than in the previous two cycles combined. ATLAS (short for A Toroidal LHC Apparatus) detects tiny subatomic fragments from particle collisions and is used to search for the Higgs boson, dark matter, and other dimensions. CMS (short for Compact Muon Solenoid) is a universal detector that uses various observation systems similar to ATLAS.

Researchers are watching the restart of the Grand Hadron Collider on April 22, 2022, to launch Run 3 on the world’s largest and most powerful particle accelerator. (Image credit: CERN / Ordan, Julien Marius; Fichet, Jacques Herve)

In addition to ATLAS and CMS, the ALICE experiment on a heavy-ion particle accelerator will be able to detect 50 times more collisions due to its upgrade, while another instrument, called the LHCb, will increase its detection capability three times. according to CERN.

“The unprecedented number of collisions will allow international teams of physicists at CERN and around the world to study the Higgs boson in great detail and subject the Standard Model of Particle Physics and its various extensions to the most stringent tests to date,” CERN officials wrote. declaration.

Two new experiments will be activated at the LHC for run 3. Called the Forward Search Experiment (FASER) and the Scattering and Neutrino Detector at the LHC (SND @ LHC), they are expected to study new physics beyond the standard model and measure how often antimatter forms and studies the physics of cosmic rays and a strange state of matter called quark-gluon plasma.

It will take several weeks of commissioning work before the revised LHC is ready for real scientific measurements. These scientific runs are expected to begin in the summer, CERN officials said.

Once Run 3 ends in 2024, CERN scientists will shut it down due to another planned overhaul that will include further improvements to the massive particle accelerator. Once these upgrades are completed, it will allow scientists to rename the LHC the “High Luminosity Large Hadron Collider” once it reopens in 2028.

Email Tariqu Malik at or follow @tariqjmalik. Follow us @Spacedotcom, Facebook and Instagram.