On April 7, 2021 researchers at the Muon g-2 experiment at Fermilab published results of their measurement of muon magnetic moment. The results differ by 4.2σ from theoretical calculations based on the Standard Model, leading to speculation that it could be a signal of new physics.
At 4.2σ, the results fall short of the threshold for a discovery (5σ), but are still unlikely enough to generate excitement. However, previous studies with high sigmas have been overturned based on systematic biases or incorrect background calculations.
Are Fermilab measurements of the muon magnetic moment indicative that the Standard Model is wrong?
The question will resolve negatively if by 2023-04-01 the concensus in the scientific literature is that the discrepancy in muon magnetic moment is <4σ compared to the Standard Model. Results could come in the form of new data, new background computations within the Standard Model, demonstration of systematic bias in the g-2 methodology, etc.
The question will resolve positively if the concensus is ≥4σ from the standard model predition. This would imply new particles, new interactions, or other new physics (although compelling theory explaining the magnetic moment is not required for a positive resolution).
If no consensus has emerged by 2023-04-01 then the resolution is ambiguous.
edit 2021-05-01: rephrased resolution criteria, expanded on 'new physics'
|Number of forecasts||48|
<iframe src="https://metaforecast-9n1bj7elb-quantified-uncertainty.vercel.app/questions/embed/metaculus-7003" height="600" width="600" frameborder="0" />