Sunday , April 18 2021

Physicists find possible clues about a new fundamental force in nature: what is it and how does it work?


April 8, 2021 00:12 GMT

The first results of an experiment from Fermi’s laboratory showed that elementary particles called “muons” behave as predicted by the standard model of particle physics.

All the forces we experience on a daily basis can be reduced to just four types: gravity, electromagnetism, strong nuclear force, and weak force. However, a group of physicists claimed to have found possible signs the fifth fundamental force of nature, which could help explain some of the big puzzles about the universe that have interested scientists in recent decades.

The first results of the U.S. Department of Energy’s Fermilab experiment “Muon g-2” – published this Wednesday in the journal Physical Review Letters – showed that elementary particles called “muons” behave in a way not anticipated. standard model of particle physics, the current generally accepted theory for explaining the behavior of the constituent elements of the universe.

Evidence that muons deviate from the calculation of this theory may suggest the existence of an “exciting new physics”the researchers wrote in a statement. “Today is a remarkable day that is not only expected by us, but by the entire international physical community,” said Graziano Venanzoni, a physicist from the National Institute of Nuclear Physics in Italy and one of the experiment’s lead scientists.

What is a muon?

A muon is a basic particle, about 200 times heavier than an electron, but smaller than an atom, which usually occurs naturally when cosmic rays hit the Earth’s atmosphere, but particle accelerators can create them in large quantities.

Like electrons, muons they act as if they have a small magnet in them. In a strong magnetic field, the direction of the muon magnet oscillates, similar to the axis of a rotator or gyroscope.

What does the experiment and its first results consist of?

The “Muon g-2” experiment consists of sending various particles around a 14-meter storage ring and then applying a magnetic field. According to the applicable laws of physics encoded in the standard model, muons should oscillate at a certain speed, which is described by a number known as the ‘g-factor’, which can be calculated with great accuracy. .

Instead, scientists found them to be muons they spun faster than expected. This could be caused by a force of nature that is completely new to science.

They are observing particles we have never seen in the Large Hadron Collider

“This number we are measuring reflects the interactions of muons with everything else in space. However, when theorists calculate the same image using all known forces and particles in a standard model, we do not get the same answer,” explained Renee Fatemi, a physicist at the University of Kentucky. and responsible for simulations of the “Muon g-2” experiment. “It simply came to our notice then muon is sensitive to something that is not in our best theory“he added.

The results of the experiment, however, are not yet a definitive discovery. Currently, there is one in 40,000 chances that the result is statistical randomness, which is equivalent to the statistical confidence level described as 4.1 sigma. We need a level of 5 sigma or one chance out of 3.5 million for observation to be a coincidence, to say it is a discovery.

“So far, we have analyzed less than 6% of the data that the experiment will eventually collect. Although these early results show us that there is an interesting difference from the standard model, we will discover much more in the coming years“said Fermilab scientist Chris Polly.

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