from Hacker News

The anomalous magnetic moment of the muon in the Standard Model: an update

by evanb on 5/28/25, 8:13 PM with 31 comments

• by jiggawatts on 5/28/25, 9:39 PM

  The reason this is big news is that modern physics theories such as quantum electrodynamics and the Standard Model can be used to calculate certain measurements such as the anomalous magnetic moment of the electron to absurdly high precision, with prediction and experiment differing in only about one part per ten billion.

  Run the same calculations for the Muon, and... err... not so good, previously differing by 3.5 standard deviations.

  Either the theory is wrong, or the experiments are wrong. The former is very interesting, because Muons are easy to experiment on, and if we can find "new physics" in something so ordinary, then it's an "accessible" regime for conditions that can be reproduced in a lab (albeit a big one).

  This paper is saying that the discrepancy has been solved by using a more fancy set of computations and newer experiments at Fermilab.

  In other words: No new exciting physics.

  Still though, this is interesting because a mystery was solved, even if the answer is in some sense boring.

• by buffer1337 on 5/29/25, 1:51 AM

  I am looking for collaborators on exploring whether geometric principles might provide a foundation for understanding how aspects of the Standard Model could emerge from simpler underlying structures. This is obviously an incredibly challenging area that many brilliant physicists have worked on, so approaching it as a learning exercise - happy to share details if anyone's interested in diving into theoretical physics rabbit holes. bufferoverflow (at) gmail.com