With every interaction between elementary particles, there is a particle associated with the transmission of the force at hand (example: the photon transmitting the e.m force).

What's the particle conveying the interaction between the Higgs field and elementary particles fields?


There is no such mediating particle or field. The interaction between the Higgs field and the fermion fields is a Yukawa interaction where a fermion bilinear directly couples to the scalar field as a term $\bar\psi\psi h$ in the Lagrangian.

In fact, you might view the Higgs itself as the mediating particle for an associated Yukawa force with potential $V(r) \propto \mathrm{e}^{-\mu r} / r$, where $\mu$ is the mass of the scalar, but since the Higgs is rather massive this "force" is so short-ranged as to be non-existent at the classical scales where it would make sense to speak of a force. The significance of this interaction in the standard model is mainly that it gives rise to the mass term of the fermions when the Higgs field acquires its VEV/mass.

  • $\begingroup$ So that makes it a point interaction? $\endgroup$ Dec 28 '16 at 14:08
  • $\begingroup$ @descheleschilder I don't really know what that's supposed to mean - what's a "point interaction"? It is the same kind of interaction as that between electrons and photons - if you want to call that a "point interaction" then it's a point interaction, if not then not. $\endgroup$
    – ACuriousMind
    Dec 28 '16 at 14:13
  • $\begingroup$ Yes, that's what I mean. The Higgs field directly couples to a fermion field, so if we assume the Higgs point-like, it hits a point-like fermion at the point where they both coïncide. Which by the way seems to me almost impossible, just as impossible like when a point-like photon meets a point-like electron. Which in turn makes you wonder if elementary particles are really point-like. $\endgroup$ Dec 28 '16 at 14:26
  • $\begingroup$ @descheleschilder A Feynman diagram is not a representation of what happens in a scattering process, but it basically represents an equation. Don't take them too literally. What we know is $m$ things goes in and $n$ things comes out and those diagrams are closely related to the probability of that happening. $\endgroup$
    – FrodCube
    Dec 28 '16 at 14:35
  • 1
    $\begingroup$ @descheleschilder "Point-like" in quantum field theory means particles that have no substructure, i.e. are elementary, not objects that are literally localized at a point. The particles of QFT are difficult to even get a notion of position/localization for, and in no way is thinking about one point "hitting" another point a useful way to think about QFT interactions. $\endgroup$
    – ACuriousMind
    Dec 28 '16 at 14:41

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