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The pair production processes like W^+ -> positron + electron neutrino W^- -> muon + muon antineutrino are allowed as are processes like W^+ -> up quark + a

The pair production processes like W^+ -> positron + electron neutrino W^- -> muon + muon antineutrino are allowed as are processes like W^+ -> up quark + anti-down quark

adrian_b 5y ago
The facts are more complex than that. Unlike the stable photon, the W bosons have a negligible lifetime. So in fact those processes listed by you that result in 2 particles are 4-particle processes. Two particles collide, either a quark and an anti-quark giving other 2 particles, a lepton + an anti-lepton (in your exemples positron + electron neutrino or muon + muon antineutrino) or a lepton collides with an anti-lepton giving a quark and an anti-quark (in your exemple up quark + anti-down quark). So there are always 4 particles, either quark, anti-quark, lepton and anti-lepton, or there may be both at input and at output a lepton and an anti-lepton, which includes the case of scattering through weak interactions, or there maybe both at input and at output a quark and an anti-quark, which includes the case when a meson decays into another meson through a weak interaction. All the interactions involving W bosons are 4-particle interactions, where the W boson is an intermediate particle that exists only during a negligible time. The 4 particles may be all at the input, all at the output, 3 at the input and 1 at the output, 1 at the input and 3 at the output or the most frequent case, 2 at the input and 2 at the output. Like all the interactions between elementary particles all these cases are equivalent and all the variants are interchangeable by moving a particle from the input to its anti-particle at the output or vice-versa. In most cases you need to pay attention only to the 4 particles participating in the weak interaction and not to the intermediate W boson. The existence of the W boson matters only when you need to compute various things because this intermediate particle transforms diagram nodes with 4 edges that cannot be computed into diagram nodes with 3 edges that can be computed with the methods of quantum electrodynamics.
- eigenket 5y ago
  Everything you've written here applies exactly the same to the Z0. I'm not sure why you insist on claiming some fundamental difference in the case of the W bosons while claiming "The neutral Z0 boson behaves like the photons"

The pair production processes like W^+ -> positron + electron neutrino W^- -> muon + muon antineutrino are allowed as are processes like W^+ -> up quark + anti-down quark

adrian_b 5y ago

The facts are more complex than that. Unlike the stable photon, the W bosons have a negligible lifetime. So in fact those processes listed by you that result in 2 particles are 4-particle processes. Two particles collide, either a quark and an anti-quark giving other 2 particles, a lepton + an anti-lepton (in your exemples positron + electron neutrino or muon + muon antineutrino) or a lepton collides with an anti-lepton giving a quark and an anti-quark (in your exemple up quark + anti-down quark). So there are always 4 particles, either quark, anti-quark, lepton and anti-lepton, or there may be both at input and at output a lepton and an anti-lepton, which includes the case of scattering through weak interactions, or there maybe both at input and at output a quark and an anti-quark, which includes the case when a meson decays into another meson through a weak interaction. All the interactions involving W bosons are 4-particle interactions, where the W boson is an intermediate particle that exists only during a negligible time. The 4 particles may be all at the input, all at the output, 3 at the input and 1 at the output, 1 at the input and 3 at the output or the most frequent case, 2 at the input and 2 at the output. Like all the interactions between elementary particles all these cases are equivalent and all the variants are interchangeable by moving a particle from the input to its anti-particle at the output or vice-versa. In most cases you need to pay attention only to the 4 particles participating in the weak interaction and not to the intermediate W boson. The existence of the W boson matters only when you need to compute various things because this intermediate particle transforms diagram nodes with 4 edges that cannot be computed into diagram nodes with 3 edges that can be computed with the methods of quantum electrodynamics.

eigenket 5y ago
Everything you've written here applies exactly the same to the Z0. I'm not sure why you insist on claiming some fundamental difference in the case of the W bosons while claiming "The neutral Z0 boson behaves like the photons"