2025 Breakthrough Prize Recognizes Collaboration Involving UT Physicists
The researchers have been working at the Large Hadron Collider in Switzerland on the ATLAS project.
A visualization of a proton-proton collision in the ATLAS detector. Image credit: ATLAS Experiment © CERN.
A single Nobel Prize in a discipline for one year can go to no more than three scientists, but this year, one of the so-called “Oscars of Science” went to thousands of physicists collaborating together around the globe.
Among them were Peter Onyisi and Tim Andeen, associate professors of physics at The University of Texas at Austin, who shared the 2025 Breakthrough Prize in Fundamental Physics with other scientists working at the Large Hadron Collider (LHC).
The Breakthrough Prize is one of the world’s largest science prizes, awarded for achievements in Fundamental Physics, Life Sciences, and Mathematics. This year, the Breakthrough Prize in Fundamental Physics was shared between several collaborations, including the ATLAS project, where scientists work on the LHC, the world’s largest particle accelerator. The $1 million of the prize allocated to ATLAS was donated to the CERN & Society Foundation for grants to doctoral students from member institutes to spend research time at CERN, the European laboratory for particle physics.
Peter Onyisi
Onyisi and Andeen both conduct research using ATLAS, one of the detectors at the Large Hadron Collider.
“We’re the world’s largest microscope,” Onyisi said. “If you’re trying to look at things that are smaller and smaller and smaller, you wind up needing things that are bigger and bigger and bigger.”
And these scientists are working with tiny particles indeed.
In 2012, researchers with the ATLAS and CMS Collaborations, including Onyisi and Andeen, announced the discovery of the Higgs boson, a fundamental particle associated with the Higgs field, which gives mass to particles like electrons. The particle had been predicted by the Standard Model of particle physics, which is scientists’ best theory of the universe. (Work related to the Standard Model also was honored back in 2020 with a Special Breakthrough Prize for UT Austin’s distinguished professor of physics Steven Weinberg, who died the following year.) Between 2015 to 2018, the physicists involved in ATLAS helped collect and analyze the data which won them the Breakthrough Prize by making measurements of the particle and demonstrating that it looked like the Higgs boson.
“Those three years represented a monumental effort to study this new thing that no one else had ever seen before and no one else could look at,” Andeen said.
The ATLAS detector, heavy as the Eiffel Tower and nearly as long as an Olympic swimming pool, helped discover the Higgs boson. Credit: ATLAS Experiment © CERN.
Using the collider, the researchers smash protons into each other 40 million times a second to increase the likelihood of observing the creation of a particle.
“I mentioned the microscope analogy, but ATLAS is a very weird kind of microscope in that you can’t choose what you put under it. Because it’s quantum mechanics, what you’re looking for is just more and more rare things,” Onyisi said. “And it could be that only one out of every 10 billion collisions will give you something that you’re interested in.”
But even when a new particle is produced from a collision, these particles decay quickly, and the scientists can only infer the presence of the particles they’re looking for.
Andeen said the Higgs boson will sometimes decay into a pair of photons, and those particles will come and interact with pieces of the Large Hadron Collider that are designed to see photons. Then, the team uses that information to reconstruct the original particle and what its properties would have been.
According to the Standard Model, any fundamental particle can be created when charged particles like protons collide, as long as enough energy is present. However, the Standard Model doesn’t account for about 95% of the universe not made of matter but instead of dark energy or dark matter.
“We explain a small fraction of the universe in great accuracy, but there are actually lots of places where we know that the theory has to be incomplete, and we’re pushing in all sorts of possible directions to see a place where we can discover something that isn’t what is predicted by the model,” Onyisi said.
Tim Andeen
Probing the limits of a model that explains the forces governing the universe might be a significant undertaking, but it’s made possible by the collaboration of thousands of people from dozens of different countries.
“We build pieces of this detector here at UT and other places around the world, and then we all bring our pieces to the site and connect it all,” Andeen said. “It’s a remarkable effort from people from around the world.”
In fact, researchers are currently working on testing pieces of the detector, including at the Physics, Math, and Astronomy Building, that will be installed on the detector starting in 2026 as part of an upgrade to ensure the experiment will be able to handle a higher collision rate and run smoothly for another 15 years.
“We have 80,000 little chips inscribed with Longhorn logos that we designed with electrical engineers here at UT that are going to go on the detector,” Andeen said.
Since the discovery of the Higgs boson, Onyisi said the physicists have been accumulating data to study more and more rare phenomena as the teams’ ultimate goal is to understand the limits of the Standard Model.
“With the Higgs boson, we had a semi-guaranteed target,” Onyisi said. “And now, we’re trying to keep our eyes in all possible directions, because we don’t know where the next big thing is going to come from.”
