CNS Physicist Stéphane Willocq Elected to Lead World’s Largest Particle Collider Experiment
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Stéphane Willocq of the College of Natural Sciences's Department of Physics has been elected as the next spokesperson for the ATLAS experiment, a collaboration of approximately 6,000 scientists worldwide who are using the Large Hadron Collider at CERN, in Switzerland, to probe the origins of the universe and to reveal its most fundamental constituents and their interactions. The team is searching for many different kinds of new phenomena, particularly for what Willocq calls the “dark sector,” or the mysterious world of dark matter, which has never been directly observed. This is the first time in ATLAS’s 30-year existence that a scientist from an institution in the U.S. has been chosen as leader of the experiment.
The ATLAS spokesperson, who serves for two years, is the de facto primary investigator leading the ATLAS effort. Willocq’s term as spokesperson will begin March 1, 2025, and he will be responsible for overseeing the operation of the experiment during what’s known as “Run 3.” The Large Hadron Collider (LHC) smashes protons together at nearly the speed of light, and the coming run will drive protons at the highest energies ever achieved in the laboratory. This will triple the amount of data that ATLAS collected during Run 2, allowing for greater statistical accuracy and opening new areas as of yet unexplored by physicists.
Willocq will also prepare ATLAS for operating at the High-Luminosity LHC, which is expected to start in 2029 or 2030. This new phase of exploration will last for over a decade and will increase the number of proton collisions by a factor of 10. It will be a monumental and exciting effort, says Willocq.
"We think dark matter is a new kind of particle that we have yet to discover, and we also think that the Higgs boson may play a role in giving dark matter particles their mass."
— Stéphane Willocq, professor of physics
“We have to make major upgrades to the particle detector and in the way we collect and process the data,” he says. “Several key detector systems will be replaced with higher performance components and the data acquisition system has to be completely overhauled.”
Willocq has been working with the ATLAS experiment for 20 years, and has helped turn the Physics department into an ATLAS hotspot, drawing his fellow physicists Benjamin Brau, Rafael Coelho Lopes de Sa, Carlo Dallapiccola and Verena Martinez Outschoorn to campus to work on ATLAS.
ATLAS discovered the elusive Higgs boson particle in 2012, along with the CMS experiment, also hosted at CERN. The Higgs boson is the key to understanding how every other particle that we know of acquires its mass and is also the key to understanding why we have different kinds of particles, and why they interact differently. Higgs bosons may also have a deep connection to the evolution of the early universe and they may provide a portal between matter as we know it and dark matter.
“We think dark matter is a new kind of particle that we have yet to discover,” says Willocq. “And we also think that the Higgs boson may play a role in giving dark matter particles their mass.”
More information about the ATLAS experiment can be found at https://atlas.cern/.
This story was originally published by the UMass News Office.
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