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harrylentil
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Even with the charge screening effect it is exact. Is there an explanation in the standard model? Can the fact there are 3 families of particles be involved?
Orodruin said:The anomaly cancelation occurs generation by generation
Vanadium 50 said:One implication of this is that a world where each family had a different unit charge - say 1.0e, 1.1e and 1.2e, would be completely internally consistent.
nikkkom said:How would muon decay look in such a world?
Wouldn't it? I have not thought much about it until you raised the issue here, but at face value it would seem to me that the muon would have a charge of 1.1e and the muon neutrino a charge of 0.1e. The decay ##\mu \to e + \nu_\mu + \bar \nu_e## would then still be possible. The different quantum numbers of the families would of course prevent any kind of mixing by forbidding Yukawa couplings between families.Vanadium 50 said:It wouldn't. I said it would be internally consistent, not that it would match our world.
Can you do that for electric charge? What you can play with should be the hypercharge. For example, the left-handed leptons forming ##SU(2)_L## doublets invariably requires a charged lepton-neutrino-W-coupling. If the neutrino was electrically neutral and the charged lepton had a different charge from the W, this would not happen.Vanadium 50 said:I was thinking in terms of a scale.
Orodruin said:Can you do that for electric charge?
While true for one generation, I do not see how you can give different generations different charges while keeping neutrinos neutral as they have to couple to the Ws and the Ws will have a fixed electric charge. Based on the Gell-Mann-Nishijima formula (which essentially just depends on how you break electroweak symmetry with the Higgs), the electric charge difference between the charged lepton and the neutrino should be the same in all generations (one if you normalise to the charge difference between the upper and lower part of the ##SU(2)## doublets - this should also set the normalisation of hypercharge). The electromagnetic current should be of the formVanadium 50 said:Sure. There is nothing in the SM that sets what the electron's elementary charge is.
But unlike hypercharge you cannot scale the SU(2) coupling constant arbitrarily between generations. It has to be the same coupling constant that appears in the non-linear kinetic gauge term or you break gauge invariance. Of course it does not have to match reality, but I am assuming that the theory is internally consistent and, that SU(2) is broken by a single Higgs so that we can still talk about electric charge. Since the EM U(1) remains unbroken, electric charge must be conserved.Vanadium 50 said:The reason this works for electric charges is because I can simultaneously scale the strength of weak isospin and weak hypercharge to make it so.
There is currently no known explanation for why the quark charge is exactly 1/3 or 2/3 the lepton charge. This is one of the fundamental mysteries of particle physics that is still being studied and researched.
Yes, the quark charge is related to the lepton charge in that they both have fractional charges. However, there is no known direct correlation or relationship between the two charges.
Yes, there have been various theoretical models proposed to explain the relationship between the quark charge and lepton charge. These include the Grand Unified Theory and the SU(5) model, but none have been proven to be the definitive explanation.
Yes, there have been numerous experiments conducted that have confirmed the fractional charges of both quarks and leptons. These experiments provide evidence for the Standard Model of particle physics, which includes the concept of fractional charges for quarks and leptons.
There is currently no evidence or proof to support the idea that the quark charge is a result of some underlying symmetry or pattern in nature. However, it is a possibility that is being explored by scientists and researchers in the field of particle physics.