Preliminary results from two experiments suggest that something may be wrong with the basic way physicists think the universe works, a prospect that the field of particle physics is stunned and excited.
Small particles called muons do not 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 rulebook that physicists use to describe and understand how the universe works on a subatomic level.
“We think we can swim all the time in a sea of background particles that just weren’t directly discovered,” Fermilab co-chief scientist Chris Polly told a news conference. “There may be monsters we could not yet imagine, and which emerge from our vacuum interacting with our muuns, and it gives us a window to see them.”
The rulebook, called the standard model, was developed about 50 years ago. Experiments carried out over decades have repeatedly confirmed that the descriptions of the particles and the forces that make up and govern the universe were quite important. Until now.
“New particles, new physics can only be beyond our research,” said particle physicist Wayne State University Alexey Petrov. “This is annoying.”
The U.S. Department of Energy’s Fermilab on Wednesday announced the results of 8.2 billion races along a track outside Chicago that while most people physicists feel excited about: the muons’ magnetic fields do not look like the standard model says they should. This follows new results published last month by the Large Hadron Collider of the European Center for Nuclear Research, which found a surprising share of particles in the aftermath of rapid collisions.
If confirmed, the U.S. results would be the largest finding in the bizarre world of subatomic particles in nearly ten years, since the discovery of the Higgs boson, often referred to as the “God Particle,” Aida El-Khadra of the University of Illinois said, working on the Fermilab experiment on theoretical physics.
The purpose of the experiments, explains Johns Hopkins University theoretical physicist David Kaplan, is to pull particles apart and find out if ‘something funny is going on’ with both particles and the seemingly empty space between them.
‘The secrets do not just live in the case. They live in something that apparently fills all the space and time. These are quantum fields, ”said Kaplan. “We put energy in the vacuum and see what comes out.”
Both sets of results involve the strange, volatile particle called the muon. The muon is the heavier cousin of the electron orbiting the center of an atom. But the muon is not part of the atom, it is unstable and normally exists only for two microseconds. After being discovered in cosmic rays in 1936, it so confused scientists that a famous physicist asked, “Who ordered it?”
“From the beginning, it puzzled physicists,” said Graziano Venanzoni, an experimental physicist from an Italian national laboratory, who is one of the best scientists in the American Fermilab experiment, named Muon g-2.
The experiment sends muons around a magnetized orbit that holds the particles long enough for researchers to take a closer look at them. Preliminary results indicate that the magnetic “rotation” of the muons is 0.1 percent lower than the standard model predicts. It may not sound like much, but for particle physicists it’s big – more than enough to advance the current concept.
Researchers need another year or two to complete the results of all the laps around the 50-foot (14-meter) orbit. If the results do not change, it will be an important discovery, Venanzoni said.
Separately, at the world’s largest atomic crusher in CERN, physicists crashed protons against each other there to see what happens next. One of the particle collisions’ different separate experiments measures what happens when particles called beauty or lower quarks collide.
The standard model predicts that these beauty quark accidents should result in equal numbers of electrons and muons. It’s like flipping a coin 1,000 times and getting about the same number of heads and tails, said Chris Parkes, head of the beauty experiment at Large Hadron Collider.
But that’s not what happened.
Researchers, Sheldon Stone, of Syracuse University, researchers researched the data from several years and found several thousand accidents and a difference of 15 percent, with significantly more electrons than muons.
No experiment is yet called an official discovery because there is still a small chance that the results are statistical features. Carrying out the experiments multiple times – planned in both cases – could reach the incredibly stringent statistical requirements for physics within a year or two to label it as a discovery, researchers said.
If the results do hold, it will increase “every other calculation made” in the world of particle physics, Kaplan said.
‘It’s not a fudge factor. This is something wrong, “said Kaplan. That something can be explained by a new particle or force.
Or these results may be errors. In 2011, it was a strange finding that a particle called neutrino moves faster than light, and this threatens the model, but this appears to be the result of a loose electrical connection problem in the experiment.
“We checked all our cable connections and we did everything in our power to check our data,” Stone said. “We’re confident, but you never know.”