The world’s biggest and most powerful physics experiment is taking place as you read this. The Large Hadron Collider (LHC), a particle accelerator and the largest machine in the world, is ready for action following a two-year shutdown.
The improvements to the LHC along with the higher energies will allow thousands of physicists around the world – including over 1,700 in the United States alone – to conduct experiments to test theories that so far have only been the province of computer simulations.
The LHC is perhaps best known for its detection in 2012 of the long-sought Higgs boson particle, thought to explain how other particles get their mass. Inside the gigantic collider, two proton beams zip around at near light speed in opposite directions. When the two beams collide, various subatomic particles, some unknown to science, are produced. The collider relies on strong magnetic fields (created by superconducting electromagnets) to guide the proton beams; the electromagnets must be chilled to minus 456.3 degrees Fahrenheit (minus 271.3 degrees Celsius), colder than outer space, so they can conduct electricity without resistance or energy loss, according to CERN.Liquid helium helps to keep the system that cold.
The upgrade was a “Herculean task,” according to the CERN statement. Teams of scientists consolidated 10,000 electrical interconnections between the magnets, added magnet protection systems and improved various other aspects of the giant collider. Protons will be bunched closer together in the beams inside the upgraded LHC, meaning more collisions.
The new-and-improved LHC will be more powerful than ever, smashing protons together at energies up to 13 trillion electron volts (TeV); for comparison, the atom smasher was running at 8 TeV when it detected the Higgs boson.
Beyond finding the Higgs boson, the LHC could produce particles predicted by a theory called supersymmetry that says every particle has a partner. These super-symmetric particles, or sparticles, in turn, could solve the mystery of dark matter, the invisible stuff in the universe that reveals itself only through its tug on normal matter.
With heavier proton beams, the LHC can recreate conditions that existed just a few billionths of a billionth of a billionth of a second after the universe was created. By studying these conditions, physicists hope to figure out why the universe is made mostly of matter and not antimatter.
About 10,000 people from 113 different countries, including seven U.S. DOE national labs and 90 U.S. universities, helped to design, build and upgrade the LHC.