Now that the Large Hadron Collider has produced what physicists strongly suspect are Higgs bosons, the physics community is starting to give the facility’s successor a bit more attention. There’s still lots more science to be done at the LHC—the groundbreaking underground facility is currently undergoing upgrades to bring its up to the planned top energy of 14 TeV—but the planned International Linear Collider promises to be what John Timmer at Ars Technica calls a “Higgs factory:”
[N]o matter how many Higgs particles pop out of the machine, there’s a limit to how much we can discover there.
That’s because the hadrons it uses create messy collisions that are hard to characterize. The solution to this is to switch to leptons, a class of particles that includes the familiar electron. Leptons present their own challenges but allow for clean collisions at precise energies, allowing the machine to produce little beyond the intended particles. So now, the international physics community is putting agreements in place that will see a new lepton collider start construction before the decade is out, most likely in Japan.
At 1 TeV, the ILC’s ultimate peak energy will be significantly less than that of the LHC, but what the ILC loses in energy it gains in accuracy and precision. Physicists hope the ILC will use its 30 km straight-shot tunnel to produce Higgs bosons and Z bosons to see how the two interact. If early experiments are successful, the bore could be extended by another 20 km.
Plans for the ILC are not yet set in stone, and results from further experiments at the LHC could alter or scuttle the project entirely. But if data from the LHC pans out, the late 2020s will be another exciting time for particle physics.