The grand explanation physicists use to describe how the universe works may have some major new flaws that need to be fixed after an elementary particle was found to have more mass than scientists thought.
“It’s not just something that’s wrong,” said Dave Toback, a particle physicist at Texas A&M University and spokesman for the US government’s Fermi National Accelerator Lab, which conducted the experiments. “It literally means something fundamental is wrong with our understanding of nature.”
The laboratory’s physicists smashed together particles over ten years and measured the mass of 4 million W bosons. These subatomic particles are responsible for a fundamental force at the center of atoms, and they only exist for a fraction of a second before breaking up into other particles.
“They keep appearing and reappearing in the quantum foam of the universe,” Toback said.
The mass difference from what the prevailing theory of the universe predicts is too large to be roundoff error or anything that could be easily explained away, according to the study by a team of 400 scientists from around the world published Thursday in the journal Science was published.
The result is so extraordinary that it needs to be confirmed by another experiment, scientists say. If confirmed, it would present one of the biggest problems yet with scientists’ detailed rulebook for the cosmos, called the Standard Model.
Duke University physicist Ashutosh V. Kotwal, the project leader for the analysis, said it’s like discovering there’s a hidden room in your house.
Scientists speculated that there may be an undiscovered particle interacting with the W boson, which could explain the difference. Perhaps dark matter, another poorly understood component of the universe, could play a role. Or maybe there’s just new physics that they just don’t understand right now, the researchers said.
The Standard Model says that a W boson should measure 80,357,000 electron volts, plus or minus six.
“We found something more than that. Not that much, but enough,” said Giorgio Chiarelli, another scientist on the Fermi team and research director at the Italian National Institute for Nuclear Physics. The Fermi team’s scale put the W boson at a more powerful 80,433,000 electron volts, plus or minus nine.
It doesn’t seem like a big difference, but it is a huge one in the subatomic world.
But both the team and experts not involved in the research said such a big claim requires additional evidence from a second team, which they don’t already have.
“It’s an incredibly delicate measurement, it requires understanding different calibrations of different small effects,” said Claudio Campagnari, a particle physicist at the University of California Santa Barbara who was not part of the Fermi team. “These guys are really good. And I take them very seriously. But I think at the end of the day we need confirmation from another experiment.”
Earlier, less accurate measurements of the W boson by other teams found it was lighter than predicted, so “maybe there’s just a little wobbly about this experiment,” said Caltech physicist Sean M. Carroll, who wasn’t involved in the research and said was “to be taken absolutely seriously”.
The finding is important because of its potential impact on the Standard Model of physics.
“Nature has facts,” said Dukes Kotwal. “The model is how we understand these facts.”
Scientists have long known that the Standard Model is imperfect. It doesn’t explain dark matter or gravity well. If scientists have to go in and tinker with it to explain those results, they need to make sure mathematical equations, which now explain and predict other particles and forces well, don’t get out of whack, the researchers said.
It’s a recurring problem with the model. A year ago, another team found another problem with the Standard Model and muon response.
“Quantum mechanics is really beautiful and weird,” Toback said. “Anyone who hasn’t delved deeply into quantum mechanics hasn’t understood it.”
Follow Seth Borenstein on Twitter at @borenbears.
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https://www.local10.com/news/world/2022/04/07/key-particle-weighs-in-a-bit-heavy-confounding-physicists/ The key particle weighs a bit heavy and confuses physicists