Europe wants to house the largest particle accelerator on Earth, which will be used to understand what 95% of the universe is made of. The new world physics mastodon, known as the Circular Collision of the Future (FCC), will be installed in a 100-kilometer perimeter underground tunnel to be built on the border between Switzerland and France. The ring will be connected to the LHC – the current most powerful accelerator in the world – with 27 kilometers in circumference.
A panel of more than 1,300 scientists from 35 countries have just presented the detailed design of this new machine, which will have seven times more power than its predecessor. The construction and commissioning of this accelerator will define particle physics for much of this century. Will be able to reach the next level in the understanding of the universe, beyond the Higgs boson and the rest of elementary particles that, together, describe the conventional matter that makes up the stars, planets, living beings and anything else in the universe visible. All that matter is less than 5% of the cosmos. The rest is totally unknown.
"We will use the different accelerators of the European particle physics laboratory [CERN] as if they were the marches of a car until reaching the maximum power ", summarizes Michael Benedikt, head of the panel of project experts.
Thanks to this scientific installation can answer "great open questions of physics," explains the physicist. The first is to understand for the first time what dark matter is made of, invisible to telescopes, but with a gravitational pull that is fundamental for galaxies to be as we see them from Earth. This mysterious component it constitutes 27% of the universe. In addition, the FCC could begin to clarify What is dark energy, the force theoretically responsible for the limits of the cosmos to continue to expand in an accelerated manner and which makes up the remaining 68% of the universe.
The estimated cost is 24,000 million euros
Everything in this new machine is huge. Its estimated cost is 24,000 million euros, it needs technologies that do not even exist today, especially superconducting magnets to accelerate and direct the particles, and will not be completed until the end of the 2050s. Europe has a great competitor. China, with all its economic potential, is going to build a very similar accelerator that could start to work a decade earlier.
"This machine will reach the maximum possible energy that we can reach with the technologies we know, it is our last cartridge," explains Carlos Lacasta, a researcher at the Corpuscular Physics Institute of Valencia and scientific secretary of the European Committee for Future Accelerators. Colliders like the LHC crash accelerated proton beams up to almost the speed of light. When they hit one another, they decompose into elementary particles. The more energy the machine reaches and the more traveled the particles in its ring, the more mass the particles that are generated. The FCC could be the first to produce particles more massive than the Higgs boson, which would already be in the territory of unknown physics. "This machine can confirm many theories, for example if it is true that what we think are elementary particles actually have even smaller components, if it is true that there is more than one Higgs boson or if there are twice as many elementary particles of the that we know, as he saysa theory of supersymmetry. The problem is that the model we have does not give us more clues as to where to go, we know that there must be much more, but we do not know what it is, "explains Lacasta.
The new installation will come into operation in phases. In the first, starting in 2040, it will use the 100-kilometer tunnel to collide electrons and positrons, its reverse antimatter. This type of facility will function as a Higgs boson factory that would help to understand in detail the properties of this particle. By the end of 2050, the improved version capable of colliding with protons, that is, entering unknown physics, would begin to operate.
If the CERN plans are carried away, there may be a gap of five years between the end of life of the LHC of high luminosity, expected around 2037, and the start of the FCC, explains Lacasta. In addition, the CERN proposal can override other accelerator projects. At the moment all eyes are on Japan, which is expected soon an announcement about whether it will eventually house the International Linear Collider. It is an accelerator with a quarter of power than the current LHC, but it allows to study the Higgs boson and its behavior with much more cleanliness. Indirectly I could also glimpse if there are signs of new physics. The project has suffered significant cuts due to lack of budget. The decision of Japan is key for Europe, which must declare in mid-2019 what scientific facilities it supports within its particle physics strategy. The FCC reminds the Superconductor Superconductor that the US tried to build in the 90s and was abandoned in the middle of the controversy because of its high cost. The new European machine will be even more expensive, although CERN has been quick to recall that the total cost of the LHC was 2.5 euros per person per year in the 22 countries that financed it. Now it remains to be seen if the FCC option convinces the international community and if other linear accelerator projects go ahead, a discussion in which there are divergent opinions from the scientific point of view and political and economic factors with even more weight. To all this is added the growing scientific power of China, determined to do things by itself, explains Toni Pich, coordinator of the National Center for Particle Physics, Astroparticles and Nuclear. "I have visited China since 1992 and I have an infinite respect. When the technology arrived it was very basic, they were many years behind schedule. They sent an army of students abroad to learn and they have already returned. Now they have the experience and also the money, so I think they can really build a 100-kilometer machine and I do not doubt that in 20 years they will be the greatest scientific power, "he explains.