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I thought all bosons were theorized to be massless. The w+and-and z bosons of the weak force are said to carry mass. Dont bosons such as the photon just pass through each other? Is that not a property of something that is not "solid"..does that mean weak bosons cannot pass through each other?

Dreamer
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  • Have you not heard of electroweak symmetry breaking? https://en.wikipedia.org/wiki/Electroweak_interaction . The weak bosons in our world are always off shell , virtual or when produced they decay very fast. – anna v Nov 11 '19 at 09:20
  • It is correct that the W and Z bosons have mass after electroweak symmetry breaking (and the photon does not because the breaking preserves a U(1) symmetry). The later comment is incorrect. Whilst the W bosons are often participants in various processes as off shell particles they can most definitely be produced as on shell particles (that later decay, yes, and so are unstable, fine) that could, in principle, be observed. Photons do not interact classically (say at tree level) because they are not electrically charged. W bosons have a self interaction at tree level. – nox Nov 11 '19 at 15:39

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Considering the full standard model theory neither fermions nor gauge bosons have explicit mass terms. However, the weak gauge bosons gain their masses during elecroweak symmetry breaking i.e. when the Higgs field acquires its non-zero vacuum expectation value. The same is true for massive fermions.

Considering your question about bosons being "solid". Self-interaction and the property of non-zero mass are completely different things. Gluons are self-interacting i.e. they can scatter off each other, while they are still considered massless. The weak gauge bosons are self-interacting even before elecroweak symmetry breaking. This is caused by the non-abelian group structure of the respective gauge groups we use to describe them.

You can take a look at the Wikipedia article of the Higgs mechanism or any book on particle physics or qft for more details.

Katermickie
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