The plan to build the most powerful supercollider ever designed has taken a major step forward with a breakthrough in controlling muon beams. If perfected, this method could increase the frequency of muon collisions enough to make it a viable option for supercollider experiments.
Currently, supercolliders rely on the collision of protons, electrons or ions to unlock the secrets of the universe, while a muon collider would allow collisions to be studied at much higher energies. Ironically, such a device would not only be more powerful, but also cheaper and easier to build, unlike the increasingly massive supercolliders already in use.
Until now, controlling muons has proven particularly difficult. For a supercollider to work properly, engineers must ensure that the subatomic particles they use actually collide. Now, a team of researchers at Imperial College London says they have discovered a new method of controlling muons that could finally make the dream of an ultra-powerful supercollider a reality.
“Our proof of principle is great news for the international particle physics community, which is preparing the next generation of high-energy accelerators,” said Dr Paul Bogdan Jurj, a researcher in Imperial’s Department of Physics and first author of a paper announcing the team’s discovery. “This is an important step towards realising a muon collider, which could be integrated into existing sites, such as FermiLab in the US, where enthusiasm for this technology is growing.”
How Physicists Use a Supercollider to Unlock the Secrets of the Universe
Although 20th-century theoretical physicists dreamed of an extremely powerful particle accelerator to help them peer into the depths of the subatomic world, the world’s first supercollider, the Large Hadron Collider (LHC) in Switzerland, didn’t begin conducting experiments until September 2008. Four years later, the 27-kilometer-long, doughnut-shaped facility made global headlines when researchers announced the discovery of the previously theoretical Higgs boson.
Twelve years later, the discovery of the subatomic particle that gives other particles their mass remains the most important discovery made by this multibillion-dollar facility. A larger supercollider, nearly 100 km long, could be built, but that facility would also take years and cost enormous sums. Moreover, like the current LHC, this facility would be limited to colliding subatomic particles that are easier to control than muons.
A supercollider capable of colliding high-energy muons would be smaller and cheaper to build and operate. The technology would also enable more powerful experiments that cannot be conducted even at CERN, giving physicists a 21st-century tool that does not yet exist.
“Muon colliders would be more compact and therefore cheaper, achieving effective energies as high as those offered by the 100 km proton collider in a much smaller space,” explains the press release announcing the team’s experimental breakthrough.
How controlling muon beams could enable more powerful experiments
To make the Super Muon Collider a reality, the Imperial College team investigated ways to control the flow of muons in a particle beam. Sometimes called “muon-marshalling,” this process has proven extremely difficult to implement, leaving previous researchers unable to crack the subatomic code.
Abstract in the journal Physics of natureThe method discovered by the Imperial College researchers involves using magnetic lenses and energy-absorbing materials to “cool” the muon beams. Previous research has shown that cooling muons in this way tends to make them move towards the centre of the beam.
In the new study, the team investigated this effect more closely, looking in more detail at the shape of the muon beam. They also studied the space occupied by the beam itself, a crucial element in facilitating particle collisions.
As expected, these experiments, conducted at the Muon Ionization Cooling Experiment (MICE) muon beamline of the Science and Technology Facilities Council’s (STFC) ISIS Neutron and Muon Beam Facility at STFC’s Rutherford Appleton Laboratory in the United Kingdom, allowed the researchers to increase the density and localization of muons in the beam. This advance means that in theory these high-energy particles could be easier to control and smash together in a superparticle collider.
Next steps towards building a muon beam supercollider
Although the muon-collecting experiments were a success, the researchers behind the discovery believe that there are still a number of steps to take to implement their work and build a real muon supercollider. Still, the team believes that solving the muon-collecting problem has paved the way for creating such a facility.
“The clear positive result shown by our new analysis gives us the confidence to move forward with larger accelerator prototypes that put the technique into practice,” said MICE collaboration spokesperson Professor Ken Long of Imperial’s Department of Physics.
Next, Dr Chris Rogers, a scientist based at STFC’s ISIS facility in Oxfordshire and leader of the MICE analysis team, says they are now focusing on developing the muon cooling system for a potential muon collider at CERN.
“This is an important result that demonstrates in the clearest possible way the cooling performance of MICE,” Rogers said. “It is now imperative to move to the next step, the Muon Cooling Demonstrator, in order to deliver the muon collider as quickly as possible.”
Christopher Plain is a science fiction and fantasy novelist and senior science editor at The Debrief. Follow and connect with him on X, Learn more about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.