4 ms·

Theres a lot of stuff here that I'm not going to pretend to be expert enough to talk about but some is definitely wrong. I think the main point that is missing

Theres a lot of stuff here that I'm not going to pretend to be expert enough to talk about but some is definitely wrong. I think the main point that is missing is that the standard model is very close to symmetric, so if you have some process that generates systems of 4 or 8 or however many particles from a neutral boson then exactly the same process should occur producing all the anti-particles of the above e.g. if you think you make 1 proton, 1 neutron, 1 electron and 1 neutrino in such a way that all the numbers balance then you should also see a process that makes 1 anti-proton, 1 anti-neutron, 1 anti-electron and 1 anti-neutrino Its also worth pointing out that pair production is not specifically an electromagnetic thing. For example the Z0 boson pair produces fermion+anti-fermion pairs in a very similar way to the photon and W bosons decay to lepton+anti-neutrino pairs in a similar way (although W bosons are charged so its a little different). The Higgs boson also decays into quark-anti-quark,lepton-anti-lepton or even boson-anti-boson pairs.

adrian_b 5y ago
You are right that that the sum of the conserved quantities can be zero also for the 8 quarks & leptons composing 1 anti-proton, 1 anti-neutron, 1 anti-electron and 1 neutrino. I did not claim that this is how matter was generated in the Big Bang, especially because for now there exists no theory for such a process. My point is that this is a strange coincidence as it would provide matter in the right proportions. Unlike for electromagnetic interactions, there might be some asymmetry making the process generating the particles more probable than the process generating the antiparticles. Because the 2 processes are decoupled, they might have happened at different rates, which is not possible with electromagnetic generation and annihilation. Of course, the correct explanation for Big Bang might be completely different, only the fact that there was no simultaneous generation of matter and anti-matter is certain. The neutral Z0 boson behaves like the photons, so I did not mention it. The charged W bosons cannot generate particle/anti-particle pairs because that would violate the conservation laws. They generate simultaneously 4 elementary particles: quark, anti-quark, lepton and anti-lepton. The quark and the anti-quark remain bound as one meson. The reverse event is also possible, but highly improbable, because it is unlikely for a meson, a charged lepton and a neutrino to collide simultaneously, in order to annihilate into W bosons. What happens frequently is the equivalent event when 2 of the 3 collide and transform into a W boson together with the antiparticle of the third. These type of events involving W bosons are what I was referring to as the generation/annihilation of systems of 4 elementary particles through weak interactions.
- eigenket 5y ago
  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"

adrian_b 5y ago

You are right that that the sum of the conserved quantities can be zero also for the 8 quarks & leptons composing 1 anti-proton, 1 anti-neutron, 1 anti-electron and 1 neutrino. I did not claim that this is how matter was generated in the Big Bang, especially because for now there exists no theory for such a process. My point is that this is a strange coincidence as it would provide matter in the right proportions. Unlike for electromagnetic interactions, there might be some asymmetry making the process generating the particles more probable than the process generating the antiparticles. Because the 2 processes are decoupled, they might have happened at different rates, which is not possible with electromagnetic generation and annihilation. Of course, the correct explanation for Big Bang might be completely different, only the fact that there was no simultaneous generation of matter and anti-matter is certain. The neutral Z0 boson behaves like the photons, so I did not mention it. The charged W bosons cannot generate particle/anti-particle pairs because that would violate the conservation laws. They generate simultaneously 4 elementary particles: quark, anti-quark, lepton and anti-lepton. The quark and the anti-quark remain bound as one meson. The reverse event is also possible, but highly improbable, because it is unlikely for a meson, a charged lepton and a neutrino to collide simultaneously, in order to annihilate into W bosons. What happens frequently is the equivalent event when 2 of the 3 collide and transform into a W boson together with the antiparticle of the third. These type of events involving W bosons are what I was referring to as the generation/annihilation of systems of 4 elementary particles through weak interactions.

eigenket 5y ago
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"