Unexpected boson measurement threatens the Standard Model of physics

After a decade of accurate measurements, scientists announced Thursday that the fundamental particle – W boson It has a much greater mass than theory, which shakes the foundations of our understanding of how the universe works.

These foundations are based on Standard Form In particle physics, it is the best theory scientists have for describing the basic building blocks of the universe, and what forces control them.

The W boson governs the so-called weak force, one of the Four basic forces Nature, and thus a pillar of the Standard Model.

But a new search Posted in Science He said that the more accurate measurement made for W Boson directly contradicts the model’s predictions.

Ashutosh Kotwal, the physicist at Duke University who led the study, told AFP that the result took more than 400 scientists over 10 years to examine four million candidate bosons from “a data set of about 450 trillion collisions.”

These collisions – which occurred by smashing particles together at dizzying speeds to study – were made by Tevatron Collider in the US state of Illinois.

The particle accelerator was the most powerful in the world until 2009, when it replaced it Large Hadron Collider Near Geneva, which is famous for the observation Higgs boson After a few years.

Tevatron stopped working in 2011, but scientists at Collider Detector in Fermilab (CDF) have been calculating the numbers since then.

Diagram showing the fundamental particles of the Standard Model. (ScienceAlert)

The ‘cracks’ in the model

The Standard Model is “probably the most successful scientific theory ever written down,” said Harry Cliff, a particle physicist at the University of Cambridge who works at the Large Hadron Collider.

“It can make fantastically accurate predictions,” he said. But if these predictions prove wrong, then not only can the model be modified.

“It’s like a house of cards, you pull a piece of it so much, everything falls apart,” Cliff told AFP.

The Standard Model is not without its problems.

For example, does not take into account dark matterwhich together with dark energy It is believed to make up 95 percent of the universe. It also says that the universe doesn’t have to exist in the first place, because the great explosion It should have exterminated itself.

Moreover, “some cracks were recently detected” in the model, the physicists said in an accompanying Science Article – commodity.

“In this framework of clues that there are missing pieces in the Standard Model, we have provided another very important and somewhat substantial piece of evidence,” Cotwal said.

“This is either a major discovery or a problem in data analysis,” said Jean Starck, a physicist and director of research at France’s CNRS Institute, anticipating “a heated discussion in the coming years.”

“Extraordinary allegations require extraordinary evidence,” he told AFP.

‘Big deal’

CDF scientists said they determined the mass of the W boson with an accuracy of 0.01 percent — twice the accuracy of previous efforts.

They compared it to a gorilla weighing 350 kilograms (800 pounds) and 40 grams (1.5 ounces).

They found that the boson was different from the Standard Model’s prediction by seven standard deviations, also called sigma.

Cliff said that if you were to flip a coin, “the chances of getting a Five Sigma result by dumb luck are one in three and a half million.”

“If this is real, and not a systematic bias or misunderstanding of how the calculations are done, this is a huge deal because it means that there is a new, fundamental component to our universe that we haven’t discovered before,” he said.

“But if you’re going to say something as big as we’ve broken the Standard Model of particle physics, and there are new particles to discover, to convince people that you probably need more than one measurement from more than one experiment.”

“It is now up to the theoretical physics community and other experiments to follow up on this and shed light on this mystery,” said CDF spokesman David Tupac.

And after a decade of measurements, Kotwal has yet to be made.

“We follow the clues and spare no effort without flipping it over, so we’ll find out what this means.”

© AFP