Atom supercollider could help unravel the Universe – 02/06/2024 – Science

Researchers at the world’s largest particle accelerator, in Switzerland, have presented proposals to create a new supercollider much larger than the current one.

Their goal is to discover new particles that would revolutionize physics and lead to a more complete understanding of how the Universe works.

If the project is approved, the new accelerator will be three times larger than the current giant machine at the European Organization for Nuclear Research (CERN).

But its price of US$15 billion (R$74.6 billion) raises concerns. A critic of the project says spending of this magnitude would be “reckless.”

This money, which is just the initial construction cost, would come from CERN member countries, including the UK. Some experts have questioned whether the project makes economic sense.

The Large Hadron Collider’s (LHC) greatest achievement so far has been the detection of a new particle called the Higgs boson in 2012. But since then its ambition to realize two great discoveries in physics, dark matter and dark energy, has not been achieved. possible.

Some of the researchers believe there are cheaper options than building a new supercollider.

The new machine is called the Future Circular Collider (FCC). Cern’s director general, Professor Fabiola Gianotti, told BBC News that, if it is approved, it will be a “beautiful machine”.

“It’s a tool that will allow humanity to make huge strides in answering fundamental physics questions about our knowledge of the Universe. And to do that we need a more powerful instrument to answer these questions,” she said.

CERN’s LHC is located on the border between Switzerland and France, near Geneva.

The LHC consists of an underground circular tunnel 27 km in circumference. It accelerates the interior of atoms (hadrons) clockwise and counterclockwise to speeds approaching the speed of light and, at certain points, collides with them with more force than any other equipment in the world.

The smaller subatomic particles left over from the collisions help scientists figure out what atoms are made of and how they interact with each other.

Revolutionary discovery

The collider’s detection of the Higgs Boson particle more than ten years ago was groundbreaking.

The existence of a building block that gives shape to all other particles in the Universe was predicted in 1964 by British physicist Peter Higgs, but was only discovered at the LHC in 2012. This was the final piece of the puzzle of current physics theory subatomic, which is called the standard model.

The proposal is that the new FCC will be built in two stages. The first part will begin operating in the mid-2040s and will collide electrons. The increase in energy is expected to produce a large number of Higgs particles for scientists to study in detail.

The second phase will begin in the 2070s and will require more powerful magnets — so advanced that they haven’t even been invented yet. Instead of electrons, heavier protons will be used in the search for new particles.

The FCC will be almost three times the circumference of the LHC — an impressive 91 km — and twice as deep.

But why does there need to be an even bigger hadron collider?

This is because the LHC, whose construction cost US$4.7 billion and began operating in 2008, has not yet been able to find particles that help explain 95% of the cosmos.

Scientists are still looking for two big unknowns. One of them is the force called dark energy, which acts as the opposite of gravity and separates objects in the Universe, such as galaxies. The other is dark matter, which cannot be detected, but its presence is felt through gravity.

“We’re missing something big,” says Gianotti.

She says the FCC is necessary because the discovery of these dark particles would lead to a new, more complete theory of how the Universe works.

More than 20 years ago, many CERN researchers predicted that the LHC would find these mysterious particles. But that never happened.

Critics like Sabine Hossenfelder of the Munich Center for Mathematical Philosophy say there is no guarantee the new collider will be successful.

“Particle physics is a large and well-funded area of ​​research for historical reasons, having grown out of nuclear physics, and it needs to get back to a reasonable size, perhaps a tenth of its current size,” she said.

A former chief scientific adviser to the UK government, Professor David King, told BBC News he believed spending $15 billion on the project would be “reckless”.

“When the world faces threats from the climate emergency, wouldn’t it make more sense to channel these research funds into efforts to create a manageable future?”

And there is also a debate among particle physicists themselves about whether a giant circular collider would be the best option to achieve the desired results.

Professor Aidan Robson, from the University of Glasgow, told the BBC that a collider built in a straight line would be cheaper.

“There are three main advantages. First, a linear machine could be made step by step. Second, the cost profile would be quite different — so the initial step would cost less. And third, the tunnel would be more short, and you could do it faster,” he said.

But the FCC is CERN’s preferred option. It is the result of extensive consultation among physicists in Europe and around the world. The center is now in the process of assessing the reaction to its proposal from its member countries, which will have to pay for the new machine.