What kind of particle smasher will succeed the Large Hadron Collider? It might seem premature to be asking that already, but it was one of the questions discussed at the International Conference on High Energy Physics in Paris, France.
Two accelerator proposals are on the table to succeed the LHC: the International Linear Collider (ILC) and the Compact Linear Collider (CLIC). The ILC would smash electrons and positrons together in a 35km-long straight accelerator, whereas the CLIC would collide them in a shorter machine but accelerate them to higher energies. (See a summary of the pros and cons of each post-LHC collider here).
So when will the next collider be chosen? No decision can be made until the LHC makes discoveries beyond the standard model of particle physics, such as evidence of "supersymmetric" particles. This will indicate which machine would be the most appropriate to further explore the properties of the new particles.
"Wishfully thinking, this could be by 2012, but more realistically by 2015 or so," said Rolf-Dieter Heuer, director general of the CERN particle physics laboratory near Geneva, Switzerland, during a press briefing at the conference today. He reckons that it will then take a further five years to secure funding and determine who will govern the project.
The LHC is expected to work until 2030. By 2020, it will have undergone an upgrade to increase the particle collision rate and produce more data. This can be done either by upping the number of particles circulating around the machine or by focusing them into a narrower beam, says Heuer.
In the shorter term, there are plans to shut down the LHC in 2012 for repairs lasting about 15 months, according to the 10-year plan presented by Steve Myers, CERN's director of accelerators and technology. After this, the machine will run for three years before another 15-month break in 2015 to start the first stage of the upgrade.