Wednesday, September 18, 2019

The Weight

For almost the last decade, physicists thought there was something weird about the proton. The subatomic particle seemed to shrink in the presence of another particle called a muon. Its diameter was 4% less in atoms where ordinary electrons were replaced with muons.

This is, to put it mildly, a big honking deal if true. Subatomic particles are not known for changing their size -- sure, they're so small that precise measurements can be tough, but recent discoveries have been able to really refine the ability of experiments to do so. If the proton grew or shrank depending on whether or not a muon was present, then a whole lotta stuff was going to be not so.

Then some physicists doing the same kind of measurements last year measured the proton with muons present and then without muons, just electrons. Turns out the earlier measurement of proton size without the muons was just wrong. They matched well within the margin of error.

None of the physicists was named Litella, although that would have been appropriate. Sometimes in science, the boring answer really is the right answer.

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