[This is a follow-up to Monday’s post, going more into depth.]
Among the known elementary particles are three cousins: the electron, the muon and the tau. The three are identical in all known experiments — they have all the same electromagnetic and weak nuclear interactions, and no strong nuclear interactions — except that they have different rest masses:
- electron rest mass: 0.000511 GeV/c2
- muon rest mass: 0.105658 GeV/c2
- tau rest mass: 1.777 GeV/c2
[These differences arise from their different interactions with the Higgs field; to learn more about this, see Chapter 22 of my book.]
Question: How sure are we that these three cousins aren’t actually the same object, seen in three different quantum states?
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