Preliminary results from two experiments suggest that there may be something wrong with the fundamental way physicists think the universe works, a prospect that has baffled and excited the field of particle physics.
Small particles called muons don’t quite do what is expected of them in two different long-term experiments in the United States and Europe. The confusing results – if proven correct – reveal major problems with the rules that physicists use to describe and understand how the universe works at the subatomic level.
“We think we’re swimming in a sea of background particles all the time that just haven’t been discovered right away,” Chris Polly, co-chief scientist on the Fermilab experiment said at a news conference. “There may be monsters we couldn’t have imagined yet emerging from the vacuum that interact with our muons and this gives us a window to see them.”
The rulebook, called the standard model, was developed about 50 years ago. Experiments conducted over decades confirmed time and again that the descriptions of the particles and the forces that make up and control the universe were quite good. Until now.
“New particles, new physics may be just outside our research,” said Alexey Petrov, particle physicist at Wayne State University. “It’s tempting.”
The U.S. Energy Department’s Fermilab announced on Wednesday the results of 8.2 billion races along a track outside of Chicago that, while ho-hum for most people has physicists in motion: the muons’ magnetic fields don’t seem to be what the standard model does. says they should be. This follows new results published last month of the European Center for Nuclear Research’s Large Hadron Collider, which found a surprising portion of the particles in the aftermath of high-speed collisions.
If confirmed, the US results would be the largest find in the bizarre world of subatomic particles in nearly 10 years, since the discovery of the Higgs boson, often referred to as the “ God Particle, ” said Aida El-Khadra of the University of London. Illinois, who is working on theoretical physics for the Fermilab experiment.
The purpose of the experiments, explains Johns Hopkins University theoretical physicist David Kaplan, is to pull particles apart and find out if there is “something funny going on” with both the particles and the seemingly empty space between them.
‘The secrets don’t just live in matter. They live in something that seems to fill all space and time. These are quantum fields, ”said Kaplan. “We put energy in the vacuum and see what comes out.”
Both sets of results relate to the strange, volatile particle called the muonThe muon is the heavier cousin of the electron that orbits in the center of an atom. But the muon is not part of the atom, it is unstable and normally only exists for two microseconds. After it was discovered in cosmic rays in 1936, it so confused scientists that a famous physicist asked, “Who ordered that?”
“From the very beginning, it made physicists scratch their heads,” said Graziano Venanzoni, an experimental physicist at an Italian national laboratory who is one of the top scientists in the US Fermilab experiment called Muon g-2.
The experiment sends muons around a magnetized track that maintains the particles long enough for researchers to get a closer look. Preliminary results suggest that the magnetic ‘spin’ of the muons is 0.1% lower than what the Standard Model predicts. That may not sound like much, but for particle physicists it is huge – more than enough to improve current understanding.
Researchers need another year or two to analyze the results of all laps around the 14-meter track. If the results don’t change, it counts as an important discovery, Venanzoni said.
Separately, at the world’s largest atomic destroyer at CERN, physicists there crashed protons against each other to see what happens next. One of several separate experiments of the particle accelerators measures what happens when particles called beauty or bottom quarks collide.
The Standard Model predicts that these beauty quark crashes should result in as many electrons as muons. It’s like flipping a coin 1,000 times and getting about the same number of heads and tails, said the Large Hadron Collider Beauty Experiment. chef Chris Parkes.
But that did not happen.
Researchers have looked at the data from several years and found a few thousand crashes a difference of 15%, with significantly more electrons than muons, said experiment researcher Sheldon Stone of Syracuse University.
Neither experiment is called an official discovery so far, as there is still a slim chance that the results are statistical idiosyncrasies. Running the experiments more often – planned in both cases – could reach the incredibly stringent statistical requirements for physics within a year or two to hail it as a discovery, researchers said.
If the results were correct, they would turn “every other calculation made” upside down in the world of particle physics, Kaplan said.
“This is not a fudge factor. This is something wrong, ”said Kaplan. That something can be explained by a new particle or force.
Or these results could be errors. In 2011, a strange finding that a particle called a neutrino appeared to be traveling faster than light threatened the model, but it turned out to be the result of a problem with the loose electrical connection in the experiment.
“We’ve checked all our cable connections and we’ve done everything we can to check our records,” said Stone. “We have a little bit of confidence, but you never know.”
Geneva AP writer Jamey Keaten contributed to this report.
Follow Seth Borenstein on Twitter at @borenbears.
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