A decade has passed since humanity officially discovered what makes our existence possible. On July 4, 2012, scientists announced the observation of the Higgs boson, the elusive particle that gives almost all other particles their mass—and thus lays the foundation for the matter that forms us and everything we see around us in the universe.
The news thrilled the world and made international headlines. Ten years later, scientists explain why the particle was so hard to find, what made its capture possible and what lies in the future.
“The Higgs is fundamentally related to key aspects of the universe. It was wonderful and amazing that we were able to discover it, and how much we’ve learned since then, but from my perspective, the work has only just begun,” said physicist David Miller, one of the many University of Chicago researchers who have worked on the Large Hadron Collider where the Higgs was discovered and where research on it continues.
“We haven’t even asked half the questions that we have about the Higgs.”
‘Hunting the snipe’
“It’s worth saying why it took so long,” said UChicago physicist Mark Oreglia, who counts more than 30 years of his career spent on the search for the Higgs. “It’s a strange particle.”
The Higgs particle is a manifestation of what is known as the Higgs field—an energy field that pervades everything in the universe. “We do not notice it; the Higgs field is like air to us, like water to fish,” wrote the Nobel committee when it awarded the research in 2013.
The particles that make us up, like electrons and quarks, interact with the Higgs field and this sets their mass. But though scientists expected there had to be a Higgs particle, they didn’t know much more than that.
“It was very much like hunting the snipe,” said Oreglia. “You didn’t know how big it was—it could have been tiny, it could have been massive. It was one of those things where you’ll know it when you see it … but you don’t know where to look.”
To search for tiny, undiscovered particles, scientists turn to accelerators. The basic idea is that if you smash particles together with enough force, they will break up into the smallest pieces that make up the universe. But even as scientists continued to build increasingly powerful accelerators that uncovered other particles, the Higgs boson remained hidden.
Finding it would require the Large Hadron Collider—the most powerful particle accelerator ever built, spanning 18 miles across the France-Switzerland border.
‘Lo and behold—there it was’
By the end of the 1990s, scientists—including those at UChicago and its affiliated national laboratories, Fermi National Accelerator Laboratory and Argonne National Laboratory—had discovered and catalogued 16 subatomic particles: all of the predicted particles except for the Higgs. That process, said UChicago physicist Mel Shochet, enabled scientists “to narrow down the range where the Higgs would have to be.” The next step was to build an accelerator that could produce and measure particles in that energy range.
The effort to design, build and operate the Large Hadron Collider involved thousands of physicists, engineers, mechanics and staff across dozens of nations. The LHC is so large that no one country could do it all; instead, individual parts of the accelerator were designed and built all around the world, then shipped to Geneva to be assembled.