...Their challenge was to understand the muon’s chains of emission and reabsorption in extreme detail. In particular, how much do the particles associated with each of nature’s four fundamental forces participate in these chains?
The calculation is straightforward for three of nature’s four forces. Gravity is so weak that physicists can ignore it outright. And both the electromagnetic force and the weak nuclear force can be deduced using a standard technique.
The strong force, however, is not so easy to deal with...
In his doctoral thesis in 2018, Keshavarzi helped hone an alternative way of understanding the strong force, called the data-driven method. In this method, physicists don’t try to predict how often muons will emit and absorb groups of quarks. They go out and measure it...
The approach resembles what happens in weather forecasting. While it is possible, in principle, to understand the weather by keeping track of the precise contour of every breeze in the atmosphere, in practice that task is absurd...
Likewise, it’s too hard for physicists to keep track of every strong-force interaction between every pair of quarks. So physicists use a technique called lattice QCD (short for quantum chromodynamics, the theory of the strong force), to use a big grid to simulate the overall behavior of quarks.
In 2014, a collaboration among researchers in Budapest, Hungary; Marseille, France; and Wuppertal, Germany — the BMW group — started on a project to use lattice QCD to calculate the muon g-factor...
In 2021, on the same day that Fermilab released its updated muon g–2 measurement, the BMW group’s result appeared in the journal Nature.
According to the BMW group’s lattice calculation, Fermilab’s muons were wobbling exactly as they should...
So why does the data-driven method indicate otherwise?
...The discrepancies point either to signs of unknown particles meddling with the quarks, or to overlooked details generating the mistaken impression that quarks are misbehaving...
“There are four decades of measurements that preceded that, that were all done in different ways, that were all done by different people, that were all done by different experiments, that all paint a completely different picture,” Keshavarzi said. “There is so much still left to do.”



Remember when Tylenol was linked to autism, crashing the stock price of its maker just long enough for that business to be acquired at a steep discount by its new owner? And how we never heard about a link between Tylenol and autism again?
I wonder which vaccine maker is about to get a hostile takeover?