After a decade of precise measurements, scientists announced Thursday that the fundamental particle – the W boson – has a mass much greater than theory, shaking the foundations of our understanding of how the universe works.
These foundations are underpinned by the Standard Model in particle physics, which 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 nature’s four fundamental forces, and thus a pillar of the Standard Model.
But new research published 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 the Tevatron collider in the US state of Illinois.
It was the world’s highest-energy particle accelerator until 2009, when it was replaced by the Large Hadron Collider near Geneva, best known for observing the Higgs boson a few years later.
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, not only can the model be modified.
“It’s like a house of cards, you pull a piece of it so much, it all falls apart,” Cliff told AFP.
The Standard Model is not without its problems.
For example, it does not take into account dark matter, which along with dark energy is thought to make up 95 percent of the universe. It also says that the universe should not have existed in the first place, because the Big Bang should have annihilated 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 the French CNRS Institute, anticipating “heated discussions 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 were to say something as big as we broke 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 do nothing without turning it over, so we’ll find out what this means.”
© AFP