It is the sheer physical size—the long tunnels, the many magnets need to fill it, and all the people needed to get that done—that makes particle colliders so expensive.
But while the cost of these colliders has ballooned, their relevance has declined. When physicists started building colliders in the s, they did not have a complete inventory of elementary particles, and they knew it. New measurements brought up new puzzles, and they built bigger colliders until, in , the picture was complete. The Standard Model still has some loose ends, but experimentally testing those would require energies at least ten billion times higher than what even the FCC could test.
The scientific case for a next larger collider is therefore presently slim. Of course, it is possible that a next larger collider would make a breakthrough discovery. Some physicists hope, for example, it could offer clues about the nature of dark matter or dark energy. Yes, one can hope. And that is assuming they are particles to begin with, for which there no evidence. Even if they are particles, moreover, highly energetic collisions may not be the best way to look for them.
Weakly interacting particles with tiny masses, for example, are not something one looks for with large colliders. And there are entirely different types of experiments that could lead to breakthroughs at far smaller costs, such as high precision measurements at low energies or increasing the masses of objects in quantum states.
In this situation, particle physicists should focus on developing new technologies that could bring colliders back in a reasonable price range and hold off digging more tunnels.
Another game-changing technology would be room-temperature superconductors that could make the strong magnets that colliders rely on more efficient and affordable.
But as the strategy update reveals, particle physicists have not woken up to their new reality. Building larger particle colliders has run its course. It has today little scientific return on investment, and at the same time almost no societal relevance.
Each machine accelerates a beam of particles to a given energy before injecting the beam into the next machine in the chain. This next machine brings the beam to an even higher energy and so on. The LHC is the last element of this chain, in which the beams reach their highest energies. The beams travel in opposite directions in separate beam pipes — two tubes kept at ultrahigh vacuum. They are guided around the accelerator ring by a strong magnetic field maintained by superconducting electromagnets.
Below a certain characteristic temperature, some materials enter a superconducting state and offer no resistance to the passage of electrical current. The accelerator is connected to a vast distribution system of liquid helium, which cools the magnets, as well as to other supply services.
What are the main goals of the LHC? What is the origin of mass? The Standard Model does not explain the origins of mass, nor why some particles are very heavy while others have no mass at all.
Particles that interact intensely with the Higgs field are heavy, while those that have feeble interactions are light. In the late s, physicists started the search for the Higgs boson, the particle associated with the Higgs field. However, finding it is not the end of the story, and researchers have to study the Higgs boson in detail to measure its properties and pin down its rarer decays. Will we discover evidence for supersymmetry? The Standard Model does not offer a unified description of all the fundamental forces, as it remains difficult to construct a theory of gravity similar to those for the other forces.
Supersymmetry — a theory that hypothesises the existence of more massive partners of the standard particles we know — could facilitate the unification of fundamental forces. What are dark matter and dark energy? Why is there far more matter than antimatter in the universe?
Matter and antimatter must have been produced in the same amounts at the time of the Big Bang, but from what we have observed so far, our Universe is made only of matter. Working in multinational teams all over the world, they are building and testing equipment and software, participating in experiments and analysing data.
The UK has a major role in the project and has scientists and engineers working on all the main experiments. In the UK, engineers and scientists at 20 research sites are involved in designing and building equipment and analysing data.
British staff based at CERN has leading roles in managing and running the collider and detectors. The total cost was shared mainly by CERN's 20 Member States, with significant contributions from the six observer nations. The LHC project involved nations in designing, building and testing equipment and software, and now continues with them participating in experiments and analysing data.
The degree of involvement varies between countries, with some able to contribute more financial and human resource than others.
It was cheaper to build an underground tunnel than acquire the equivalent land above ground. Putting the machine underground also greatly reduces the environmental impact of the LHC and associated activities. The rock surrounding the LHC is a natural shield that reduces the amount of natural radiation that reaches the LHC and this reduces interference with the detectors.
Vice versa, the radiation produced when the LHC is running is safely shielded to the surroundings by 50 — metres of rock. What they actually mean is:.
CERN has never been involved in research on nuclear power or nuclear weapons, but has done much to increase our understanding of the fundamental structure of the atom. The title CERN is actually an historical remnant, from the name of the council that was founded to establish a European organisation for world-class physics research. Firstly, CERN and the scientists and engineers working there and their research have no interest in weapons research.
They are dedicated in trying to understand how the world works, and most definitely not how to destroy it. Secondly, the high energy particle beams produced at the LHC require a huge machine consuming MW of power and holds 91 tonnes of super-cooled liquid helium.
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