Mayank Chhaya at the Fermilab in Batavia, near Chicago. (Photo: MC)*
It is time for me to visit the iconic Fermilab in Batavia again. This time to understand whether and how scientists there have found a new force of nature, a fifth force apart from the other four known fundamental ones so far. They are gravitational, electromagnetic, strong, and weak. I know that “strong force” and “weak force” do not sound particularly exciting or convincing but trust me they exist and are all key to what the universe is.
The last time I visited the Fermilab was in September 2016 to interview a young scientist about Dark Matter which too seems as illusive as this new force. Like the great Albert Einstein said everything about the universe at its operational level subtle. The unfathomable spectacle called the universe that we see stems from aching subtlety as constituted by a variety of particles.
Speaking of particles, there is one called muons. Those are the particles at the heart of the announcement by the Fermilab of what could well be a fifth fundamental force of nature.
“The long-awaited first results from the Muon g-2 (expressed as g minus 2) experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory show fundamental particles called muons behaving in a way that is not predicted by scientists’ best theory, the Standard Model of particle physics. This landmark result, made with unprecedented precision, confirms a discrepancy that has been gnawing at researchers for decades,” the Fermilab said in an announcement.
“The strong evidence that muons deviate from the Standard Model calculation might hint at exciting new physics. Muons act as a window into the subatomic world and could be interacting with yet undiscovered particles or forces,” the laboratory said.
If the fifth force is indeed confirmed with the finality of all the scientific weight, then as the lab says we are entering the era of a new physics. I am quoting directly from the press release because it explains in great detail what the likely breakthrough means.
“A muon is about 200 times as massive as its cousin, the electron. Muons occur naturally when cosmic rays strike Earth’s atmosphere, and particle accelerators at Fermilab can produce them in large numbers. Like electrons, muons act as if they have a tiny internal magnet. In a strong magnetic field, the direction of the muon’s magnet precesses, or wobbles, much like the axis of a spinning top or gyroscope. The strength of the internal magnet determines the rate that the muon precesses in an external magnetic field and is described by a number that physicists call the g-factor. This number can be calculated with ultra-high precision.
As the muons circulate in the Muon g-2 magnet, they also interact with a quantum foam of subatomic particles popping in and out of existence. Interactions with these short-lived particles affect the value of the g-factor, causing the muons’ precession to speed up or slow down very slightly. The Standard Model predicts this so-called anomalous magnetic moment extremely precisely. But if the quantum foam contains additional forces or particles not accounted for by the Standard Model, that would tweak the muon g-factor further,” it says.
I know the following is very difficult to grasp but this the crux of the possible discovery.
The accepted theoretical values for the muon are:
g-factor: 2.00233183620(86)
anomalous magnetic moment: 0.00116591810(43)
[uncertainty in parentheses]
The new experimental world-average results announced by the Muon g-2 collaboration today are:
g-factor: 2.00233184122(82)
anomalous magnetic moment: 0.00116592061(41)
These results have been given a significance of 4.2 sigma, sigma being the scale by which potential discoveries are graded. 5 sigma is the gold standard by which 4.2 is not bad at all but still not absolute proof of a fifth force. Like I said at that level of physics everything just too subtle and hence illusive.
It is possible that this result could well establish a fifth fundamental force of nature.
I intend to do a story on this from my just inaugurated show ‘Mayank Chhaya Reports’. I will do an initial story this Saturday on my Facebook and YouTube pages.
*I have used my photograph at the Fermilab from 2016 wholly unnecessarily.