Meanwhile, in 2020, a group of 170 experts, known as the Muon g-2 Theory Initiative, published a new consensus value on the theoretical value of the magnetic moment of the muon, based on three-year workshops and calculations using the Standard Model. This response reinforced the initial discrepancy reported by Brookhaven.
Reached over the phone on Monday, Aida X. El-Hardra, a physicist at the University of Illinois and co-chair of the Muon g-2 theory initiative, said she did not know the result Fermilab would announce two days later – and she did not want to. so as not to be tempted to invent a lecture scheduled just before the official opening on Wednesday.
On the day of the announcement of Fermilab, another group, using a different technique known as grid calculation to calculate the magnetic moment of the muon, came to the conclusion that there was no discrepancy between the Brookhaven measurement and the Standard Model.
“Yes, we claim that there is no discrepancy between the standard model and the Brookhaven result, there is no new physics,” said Zoltan Fodor of Pennsylvania State University, one of the authors of a report published Wednesday in Nature.
Dr. El-Hadra, who was familiar with the work, called it “an incredible calculation, but not a convincing one.” She noted that the calculations involved were terribly complex, taking into account all the possible ways in which the muon could interact with the universe, and required thousands of individual calculations and hundreds of hours of supercomputer time.
These grid calculations, she said, should be checked against independent results from other groups to eliminate the possibility of system errors. For now, the calculation of the Theory Initiative remains the standard by which the measurements will be compared.