In Practice: What is the future for experimental physics?

Sneha Malde works for the LHCb experiment: “I think there’s a lot of interesting work that can be done in the next 20 years … I’d like to really help drive things forward.” (Image: Maximilien Brice/ CERN)

In 2012, the discovery of the Higgs boson was front-page news worldwide. So, what has been happening at CERN and the Large Hadron Collider (LHC) since?

The reality is that scientists, engineers and technicians at CERN are working harder than ever to deliver impressive performances of the accelerators, detectors, and infrastructure. Experimental physicists are busy analysing the huge amounts of data amassed during the LHC’s first and second runs. Small discoveries are being made daily.

“In terms of science it is what it is and maybe we are looking in the wrong place. Maybe we should be doing something else,” explains Sneha Malde, a researcher working for one of the LHC experiments, LHCb. “But I hope…I have a strong feeling that we will find something. I’m quite excited by the prospect of what particle physics can do in 20 years or even 10 years from now.”

One of the plans for future physics discoveries is through the construction of the High-Luminosity LHC. This requires several new technologies, including innovative super-conducting cables that are now being produced at CERN. The image shows the production of a long length Rutherford cable, made from 40 made from a state-of-the-art Nb3Sn strands, that will be used in a HL-LHC dipole magnet. The wiring machine is the only one left in Europe able to do such a job (Image: Maximilien Brice/CERN)

With such incremental movements forward, how can CERN capture the world’s attention? Attention that is crucial since, without public interest and excitement, it could be challenging for future projects to receive public funding.

Without a front-page headline, could it mean the end for experimental physics and the careers of experimental physicists themselves?

Beyond the Discovery

Personalities and History of CERN
“I can understand that there might be excitement in discovery but there’s also excitement afterwards, in measuring the properties of what’s been discovered. It often leads to something new and that’s part of the excitement too” – Nadjieh Jafari, CMS (Image: Sophia Bennett/CERN)

Nadjieh Jafari works on the physics of the top quark – an elementary particle and a fundamental constituent of matter. Even though the top quark was found more than twenty years ago, Nadjieh’s work proves that a discovery, particularly a discovery that supports a specific scientific theory, doesn’t mark the end to an area of physics.

This is something physicists at CERN today know well, as work on the Higgs boson didn’t stop once it was shown to exist. Many still work on it each day, trying to gain an ever deeper insight into its properties. In fact, for them, the discovery was just the beginning.

If just one of these properties doesn’t match the Standard Model’s prediction, then it opens a whole world of new physics, potential new theories and possible new particles to be discovered. Unfortunately, so far the boson has stubbornly fitted every single parameter that physicists expected of it – seemingly their predictions were just too good.

Siegfried Fortsch doesn’t believe this is a problem though. He likens physicists to ancient explorers; setting off in search of new worlds expecting to find one thing but discovering, many years later, they’d made an even bigger discovery than originally thought. 

Personalities and History of CERN
“Experimentalists are like the sailors who accompanied Christopher Colombus. They wanted to find India, but we know they didn’t discover it, they discovered something completely different,” says Siegfried Fortsch (Image: Sophia Bennett/CERN)

“One century from now, most of what we’re building will be part of everyday technology. When we discovered the electron a century ago, who would have known that our lives would become so much better for that discovery, with electricity? It could also be the case for the particles we are discovering now. I would be excited to see that but I won’t be here,” Jafari adds.

“The more we know from the LHC, the sharper our ideas become.” ­– Nadjieh Jafari, physicist at the CMS experiment

Where will new physics come from?

“We’ve looked into the easy places,” explains Jamie Boyd, LHC programme coordinator. “But now we need to look into harder places. It’s why you talk of the next project, if they think there’s nothing else interesting in the LHC we need to go to a higher energy.”

CERN has long-term plans to continue the work of the LHC. From maintenance being done currently, during the extended year end technical stop (EYETS), which runs from now until spring 2017, to the more substantial LHC upgrade with the approved High-Luminosity LHC (HL-LHC) project.

The High-Luminosity LHC, which should be operational by 2025, will allow precise studies of the new particles observed at the LHC and will allow physicists to observe the rare processes that are inaccessible at the LHC’s current sensitivity level.  But even beyond HL-LHC, more ambitious projects and experiments are being imagined. At the moment, several research and development studies are underway, including the Compact Linear Collider (CLIC) and the Future Circular Collider study (FCC).

Guido Tonelli, former spokesperson of the CMS experiment who worked on the Higgs boson discovery, reflects on a time in the 1980's when the LHC's predecessor, the Large Electron-Positron Collider, was being built, and what the future for circular colliders might be (Video: Jacques Fichet/CERN)

“It’s super interesting but it’s challenging to build and challenging to fund,” explains Boyd. “But decisions about future projects, like the FCC, will probably depend on what we see with the LHC. The end of 2018 will be the time. If we haven’t seen new particles then it will tell us something about how we’re looking for things. Now it’s too early to say.”

New studies that push the boundaries of technology and look far ahead, and the potential energy and luminosity levels we can reach, ignite excitement among researchers, engineers and technicians for the next stage of experiments, and the future.

Whether the future of particle physics lies in higher energies, higher luminosities, something else or even completely un-thought of experiments, there are still plenty more discoveries to be made – the future is most definitely bright.

To learn more about experimental physics and the physicists working on the experiments, read the rest of our In Practice series.