Next month, humanity’s most powerful and expensive tool for breaking stuff at the subatomic level, and possibly its best hope for figuring out some of the fundamental building blocks of the universe, will return to operation after a two-year hiatus (a hiatus which was necessary for planned maintenance operations). CERN’s Large Hadron Collider (LHC) is back in business, shinier, stronger and more powerful than ever.
The LHC is widely regarded as being among the largest and most complex machines that humans have ever built. When it shut down in 2013 after its first three years of operation, it was coming off its most important achievement: Collisions initiated in 2012 had resulted in the production of a particle whose properties matched those predicted of the Higgs boson—the linchpin holding together the Standard Model of particle physics.
In detecting the Higgs boson, the machine fulfilled its basic promise as the device which would help physicists answer some of the most difficult open questions in the field. But in science, there is rarely a shortage of unanswered questions, and the past two years have been spent getting the LHC infrastructure ready to plumb even further into the depths of particle physics.
According to CERN, engineers and technicians have replaced 18 of the superconducting dipole magnets that steer particles through the accelerator, upgraded 10,000 electrical connections in the facility, narrowed the beam width of the particle streams, and increased the voltages used to amplify the beams. They have improved the cryogenic systems used to keep the dipole magnets at temperatures low enough to maintain their superconducting state and installed more radiation resistant electronics. The interior of the beam pipe (which is kept under vacuum to prevent the beam from inadvertently colliding with air molecules) has been coated with a material called “non-evaporable getter,” which helps prevent electrons from being ripped off the interior surface of the pipe itself and interfering with the beam.
All these improvements have served to nearly double the collision energy for future experiments, moving up to 13 TeV from 8 TeV.
With the increased collision energy available, physicists are going to be hunting bigger game when the collider comes back online. Supersymmetry will be the target as scientists smash the beams together again in search of the gluino — the hypothetical partner particle of the gluon, the elementary particle responsible for the strong force interaction.
To date, the results of LHC experiments have tended to cast doubt on the theory of supersymmetry, so uncovering a gluino would be a major discovery. But even if the hypothetical particle is not discovered, the LHC has plenty of other mysteries to probe during its second run, including further research on the Higgs boson, investigations into antimatter, extra dimensions, and exotic particles which might only be exposed through interaction with the Higgs field.