# Which bosons are used to mediate the electroweak force?

## Main Question or Discussion Point

The electroweak force is a unified force that combines both electromagnetism and the weak nuclear force. But since the electromagnetic force is mediated by photons and the weak nuclear force is mediated by W & Z bosons, which of these particles actually mediates the electroweak force? Is it the photons, the W & Z bosons, or all three particles?

## Answers and Replies

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The electroweak force is a unified force that combines both electromagnetism and the weak nuclear force. But since the electromagnetic force is mediated by photons and the weak nuclear force is mediated by W & Z bosons, which of these particles actually mediates the electroweak force? Is it the photons, the W & Z bosons, or all three particles?
All four particles (W+, W-, Z0, and γ) mediate the EW force.

BBB

That means that when the electroweak force is acting on an object, all four particles are acting at once.

Another interesting question: since the W+ and the W- particles have electric charge, does that mean that they use photons for their electromagnetic fields?

That means that when the electroweak force is acting on an object, all four particles are acting at once.
In a manner of speaking that's true enough (presumably you mean at high energies).

Another interesting question: since the W+ and the W- particles have electric charge, does that mean that they use photons for their electromagnetic fields?
Yes, by definition, since electromagnetic fields are only ever made of photons. These things don't live long enough to bother thinking about their interactions with photons in this classically-oriented way though. You are never going to see one leave a curved track in a magnetic field or anything.

naima
Gold Member
Hi Kurros,

The gluons selfinteract because they carry color charges.
Why cannot we use this logic for W ?

Yes, by definition, since electromagnetic fields are only ever made of photons. These things don't live long enough to bother thinking about their interactions with photons in this classically-oriented way though. You are never going to see one leave a curved track in a magnetic field or anything.
The question did not ask about the interaction of the W bosons with the photons, only if the W bosons use photons for their electromagnetic fields. Of course with a half life of only 3x10−25s the effect of the photons on the W bosons is negligible since the W bosons quickly transform into other types of particles.

Hi Kurros,

The gluons selfinteract because they carry color charges.
Why cannot we use this logic for W ?
You can, and they do. This random webpage I found just now http://acfahep.kek.jp/acfareport/node182.html" [Broken] has a list of the "self-interaction" vertices of the electroweak gauge bosons in table 6.1. You will notice there is a WWWW coupling, and also WWZ, among others.

The question did not ask about the interaction of the W bosons with the photons, only if the W bosons use photons for their electromagnetic fields.
I just threw that in as a bonus. Did the first part of my response not answer your question?

Of course with a half life of only 3x10−25s the effect of the photons on the W bosons is negligible since the W bosons quickly transform into other types of particles.
Most of the time I think that's probably true, but W bosons themselves are basically negligible most of the time (the Fermi effective theory will do); In modern high energy collisions, however, it is very important and not at all negligible.

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naima
Gold Member
Thank you, you are right
I also found
[PLAIN]http://www.rug.nl/kvi/research/kvitrimp/researchdescription/trix/screening_cropped.jpg [Broken]
where a W loop gives a photon

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Thank you, you are right
I also found
where a W loop gives a photon
Indeed, WWγ is also in the list I mentioned. Things are a bit more complicated than in QCD or QED because the concept of charge is not as "straightforward", since it gets somewhat mangled up during symmetry breaking, but the basic idea is there.

I just threw that in as a bonus. Did the first part of my response not answer your question?
The original question was answered and the bonus information is of course appreciated.