“CERN is like Disneyland for physicists”

“I thought it was completely normal, that this was just business as usual. I was so young and I didn’t know anything,” laughs Rebeca Gonzalez Suarez when we meet her at the Ångström Laboratory – which is where she works when not at CERN in Geneva.

There is no mistaking Gonzalez Suarez’s passion for particle physics. Her office in Uppsala is full of objects that bear witness to this. Magnets adorned with the elementary particles of the Standard Model sit on a whiteboard. On the bookshelf above the desk, the books stand alongside miniature models of CERN’s ATLAS and CMS detectors, a hard drive with the first signals from the Higgs boson and a china dog with a CERN leash. Beside her desk there is a collection of soft toys representing the various elementary particles she is researching – including the Higgs boson.

The discovery of the Higgs boson in 2012 was a milestone not only in her career but also in particle physics. After more than half a century of attempts to confirm its existence, the experiments at the Large Hadron Collider (LHC) at CERN, in which Gonzalez Suarez participated, finally succeeded.

World’s largest particle accelerator

The LHC, which consists of a 27-kilometre ring in an underground tunnel, is the world’s largest particle accelerator facility. In it, proton beams are accelerated to close to the speed of light before colliding. In this way, scientists are trying to recreate the time just after the Big Bang when all matter in the universe arose out of interactions between different elementary particles. Many of these particles were extremely short-lived, like the Higgs boson.

“The most massive particles no longer exist because they fell apart after the Big Bang,” Gonzalez Suarez explains.

With the discovery of the Higgs boson, all the pieces of the basic Standard Model of particle physics* fell into place. According to the theory, elementary particles acquire their mass in the Higgs field. But to confirm the existence of the Higgs field, one more particle was needed: the Higgs boson.

Signals of the Higgs boson

Gonzalez Suarez first came to CERN in 2008. When she and the other researchers started looking for signals of the Higgs boson in their experiments, it was far from certain that it would be found.

“It was great fun. We received data and accumulated it and analysed it, so it was really, really exciting. When I was working on my thesis, we hadn’t found the Higgs yet, but from the data we had we could already see that it would happen,” says Gonzalez Suarez.

CERN attracts thousands of scientists from all over the world looking for answers to the big questions in physics.

“Being at CERN is really special because it’s an interesting place. When I was a young student, I was interviewed about my experiment and I said it was like Disneyland for physicists. Every time I go there, it feels exciting. I talk to everyone there. We get new ideas, meet other people from every city and part of the world. I love CERN so I go there very often because it’s good to be there. But many of us work remotely, that’s the set-up. Our resources are at CERN, but we work at different universities around the world,” Gonzalez Suarez explains.

So what does a typical day at CERN look like?

“I do a lot of different things: a lot of meetings, analysis meetings with people I work with, but also coffee. We have coffee and talk about ideas with colleagues and friends. But we also work shifts. The machines have to run 24 hours a day. We have to be there in the control room, each shift lasts for eight hours. I love being there too because it’s fun to see the data coming in,” she says.

Want to reveal dark matter

One of the really big questions Gonzalez Suarez personally wants an answer to is what dark matter is. According to astronomers and physicists, there should be much, much more matter in the universe than can be observed using telescopes and other conventional means. Otherwise it is difficult to explain why, for example, galaxies are spinning faster than the light they emit would suggest. This discrepancy is thought to be due to the presence of dark matter, a kind of alien and invisible matter. Gonzalez Suarez has an idea that dark matter could consist of as yet unknown particles.

However, she is not just involved in pure research. According to current plans, around 2042 CERN will retire the Large Hadron Collider.

“After that, the idea is for us to have another, even bigger collider. And we have to plan it now. For the last five years I have been working a lot on planning the future collider so I am very involved in this,” says Gonzalez Suarez.

Push the boundaries

By means of the new Future Circular Collider particle accelerator, it is envisaged that research will be able to truly push the boundaries of the Standard Model of particle physics and rethink it. For Gonzalez Suarez, and many others, believe the model is imperfect and may need to be revised as we learn more about elementary particles and how they interact with each other.

CERN has shaped her life in many ways. It was also there that she met her Swedish husband, who was then a doctoral student at Uppsala University. He spoke so highly and enthusiastically of his university that the couple moved to Sweden in 2018.

Gonzales Suarez came straight to Uppsala University. Here she gets to combine two of the best things in her world: research and teaching.

“The students are so nice here,” she says.

Åsa Malmberg

*Footnote: The Standard Model of particle physics describes how elementary particles build up matter and how they interact with each other through electromagnetic, strong and weak interactions.