I find this somewhat baffling. 4% just seems like such a huge disparity, especially for such a ubiquitous particle. It seems like any experiments before 2010, t

I find this somewhat baffling. 4% just seems like such a huge disparity, especially for such a ubiquitous particle. It seems like any experiments before 2010, that used the size of a proton in the calculations should have noticed something was wrong. Fermilab has spent the last couple years trying spruce up an old experiment to measure the dipole-moment of the muon down to 0.14 ppm[1][2] Apparently that small of a discrepancy in theory and experiment was interesting enough to throw a huge amount of time into. How is it that we are trying to verify the 9th significant digit in the dipole moment of an obscure particle, while something as mundane as the size of the proton was off by 4%? Obviously, I'm missing something. [1]https://en.wikipedia.org/wiki/Muon_g-2 https://en.wikipedia.org/wiki/Muon_g-2 [2]https://www.youtube.com/watch?v=UckuqHDB08I https://www.youtube.com/watch?v=UckuqHDB08I