I just read an article in Science News (p7, 11/10/2018, link here) where researchers looked for an electric dipole moment in an electron. They spoke of charge separation between the positive and negative charges. I thought the electron was a basic particle. Does it have sub-particles?
[Physics] n electric dipole moment in an electron
dipole-momentelectronselementary-particles
Best Answer
The electron is a fundamental point particle. It does not have sub-particles “inside”. However, its quantum interactions with other particles should give it a small electric dipole moment, according to the Standard Model of particle physics. (It is a very difficult calculation but there are estimates for it.)
Some people like to picture this in their minds as a halo of virtual particles - photons, electrons and positrons, quarks and antiquarks, etc. — surrounding the electron. Don’t take this picture too seriously, but the mathematics tells us that the dipole moment does come from the interaction of the electron’s quantum field with other quantum fields present in the quantum vacuum.
Once experiments become sensitive enough to measure the electron’s dipole moment, they will be a very good test of the Standard Model. If the expected dipole moment is not found, that will be a big deal. If it has a different value than predicted, it could mean that the electron is interacting with particles we don’t know about! Imagine finding evidence for a new particle this way, without having to build a giant accelerator!