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Dumb question that I feel I may have asked before, but that I don't recall the answer to: Why does it seem like everyone believes the number of "fundamental" p
by mehrdadn 8y ago
Dumb question that I feel I may have asked before, but that I don't recall the answer to:
Why does it seem like everyone believes the number of "fundamental" particles is finite? What fundamental reason is there for this?
- bufferoverflow 8y ago[citation needed] I've never seen any major institution/publication to claim the number of fundamental particles is finite. We discover new ones as we go. Nobody is really shocked these days.
- mehrdadn 8y agoI've never seen them say it explicitly, but every article I read seems to be along the lines of "physicists thought/hoped the standard model could be complete, but then this little particle came along...". Even the fact that they think they can have a model with a finite number of particles gives the impression they think this is more likely than not to be the case.
- pixl97 8y agoBecause there is no evidence of an infinite number of different fundamental particles.
- api 8y agoWhat would constitute evidence of this? The 1000th particle? 10000th? You can always argue that may be the last one.
- pixl97 8y agoParticles have energy levels. There is a maximum energy level and a minimum energy level. We already know that every energy level does not have a particle associated with it (quanta). Therefore there cannot be an infinite number of particles.
- mehrdadn 8y agoWhat would count as evidence for this?
- pixl97 8y agoParticles have energy levels. There is a maximum energy level and a minimum energy level. We already know that every energy level does not have a particle associated with it (quanta). Therefore there cannot be an infinite number of particles.
- mehrdadn 8y agoHuh, interesting. What is the maximum energy level a particle can theoretically have? How do we know it is the maximum?
- pixl97 8y agohttps://en.m.wikipedia.org/wiki/Absolute_hot https://en.m.wikipedia.org/wiki/Absolute_hot Tl;dr, put enough energy in a particle and it turns into a singularity.
- gus_massa 8y agoIIRC there is some experiment where a particle split spontaneously in a pair of neutrino-antineutrino. Each type of neutrino has the same probability. In that experiment they get that only 1/3 of particles are split into "electron neutrinos", so they deduce that there are only three types of neutrinos ("electron neutrinos" / "muon neutrinos" / "tau neutrinos"). So now they are measuring another neutrino that is "sterile" for some reason doesn't appear in that experiment. ---- Edit: [Perhaps more accurate] Wikipedia links to https://www.sciencedirect.com/science/article/pii/0370269389907041?via%3Dihub https://www.sciencedirect.com/science/article/pii/0370269389... that says: > With the constraints of the standard electroweak model, the number of light neutrino species is found to be Nv=3.27±0.30. this results rules out of the possibility of a fourth type of light neutrino at 98% CL.