Every time I try to understand how forces which hold atoms and molecules together work, I find myself wanting to ask this question: why not the other way around? Could there be an atom which has electrons and neutrons inside, and protons outside?

It feels like a silly question, but is there something we know about the universe we live in that implies that this is not possible?

  • liwott@nerdica.net
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    8 months ago

    Electrons are not subject to the strong nuclear force that glues the protons neutrons together. This means that no attractive force would prevent electric repulsion to scatter a “electron nucleus”.

    From a field theory perspective, the strong nuclear force is a SU(3) gauge interaction and the electron field transforms as a singlet under that SU(3)

    • neidu2@feddit.nl
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      8 months ago

      This was my thoughts to. Electrons don’t clump together on their own. Do gluons even affect electrons at all, or is that more of a baryonic thing?

      • liwott@nerdica.net
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        8 months ago

        Strong interaction is really designed as a baryonic thing, leptons have no color charge (which is another way to say that they transform as SU(3) singlets). Leptons do not interact with gluons.
        Not at tree-level anyway. See for example this list of vertices.

        At loop levels, it’s possible to imagine an electron decaying into neutrino+W, then W into two quarks who can then interact with gluons, but as it’s down a couple of orders in perturbation theory so probably much too weak to hold a nucleus together. Not an expert in particle physics so I do not know with certainty whether a couple-of-loops interaction can have a measurable effect.