A fifth fundamental force in physics was suggested by muon experiments in Science & Tech News
A scientific experiment has produced evidence that researchers believe indicates a previously undiscovered fundamental force in physics.
All interactions in the natural universe – from a hand catching a ball falling from the sky to magnetism and radioactive decay – are based on four fundamental forces.
Physicists largely understand how these four forces – gravity, electromagnetism, the strong nuclear force (which holds matter together), and the weak nuclear force (which causes matter to fall apart) – work together in a given situation.
However, a recent experiment at Argonne National’s high-tech laboratory outside of Chicago provided “strong evidence” that there may be a fifth fundamental force or previously undiscovered subatomic particle that science is ignorant of.
The research was funded by the US Department of Energy, which operates the Argonne National Laboratory and the Fermi National Accelerator Laboratory in the US along with staff from 46 other institutions in seven countries.
The experiment, known as muon g-2 (pronounced muon g minus 2), is the latest that explores the limits of human knowledge of the elementary particles that make up the universe.
It examined a muon – a kind of unstable elementary particle similar to the electron – and in particular the muon’s g-factor, a value that describes how the particle behaves in a magnetic field.
According to the standard model of physics, the g-factor of the muon should be two. The experiments aim to investigate how much the g-factor actually deviates from two, hence the name muon g-2.
A discrepancy between the predicted and the actually observed g-factor was first discovered in 2006 at the Brookhaven National Laboratory in New York.
The Standard Model states that muons, like electrons, are electrically charged so they are expected to rotate when placed in a magnetic field.
Scientists can observe this spin due to something called a precession, which causes the axis of the spinning particle to wobble, meaning humans can observe something called a wobble plot.
Now, new research has confirmed that the wobble plot for the muon is much larger than predicted by the Standard Model, and scientists believe the probability that this deviation is the result of a measurement error is about 1 in 40,000.
“This is an incredibly exciting result,” said Dr. Ran Hong of Argonne National Laboratory, a postdoctoral fellow who worked on the experiment for over four years.
“These results could have a significant impact on future particle physics experiments and lead to a better understanding of how the universe works,” added Dr. Hong added.
“These new physics could help explain longstanding scientific secrets, and the new findings complement a repository of information that scientists can use as they model our universe and develop new technologies,” said the Argonne laboratory.