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> There have been actually many positive theories trying to explain what particles dark matter could be, they've all been proven wrong. Not at all. Ordinary ne
by nyssos 3y ago
> There have been actually many positive theories trying to explain what particles dark matter could be, they've all been proven wrong.
Not at all. Ordinary neutrinos and MACHOs (black holes, rogue gas giants, extremely faint dwarf stars) are mostly ruled out. Supersymmetry is not looking promising but certainly not proven wrong. Sterile neutrinos and axions are very much live candidates.
> However, we are now left with no room in our understanding of particles
There's plenty of room. Quantum gravity is obviously the elephant in the room, but even aside from that, and off the top of my head: the standard model doesn't account for neutrino masses ,matter/antimatter asymmetry, or why the lepton masses are related, and it gets the magnetic moment of the muon wrong. The existence of physics beyond the standard model is certain. We just don't know what it is yet.
- jboy55 3y ago>Quantum gravity is obviously the elephant in the room, Isn't that just our understanding of gravity not being complete. > the standard model doesn't account for neutrino masses ,matter/antimatter asymmetry, or why the lepton masses are related, and it gets the magnetic moment of the muon wrong. The existence of physics beyond the standard model is certain. That seems to be a big leap, is not the existence of flaws in our understanding of gravity also certain?
- nyssos 3y ago> Isn't that just our understanding of gravity not being complete. No. It's that, but it's not just that: if a QFT in 4-d spacetime has a coupling constant with a negative mass dimension, it has infinitely many free parameters, which means you can only use it below a given energy scale. We live in a 4-d spacetime, and the mass dimension of Newton's constant is -2, so either the true theory is not a QFT, or it's an infinitely complicated QFT we can never actually find. > That seems to be a big leap, is not the existence of flaws in our understanding of gravity also certain? Yes, both GR and the standard model are known to be incomplete.
- ben_w 3y ago> It's that, but it's not just that: if a QFT in 4-d spacetime has a coupling constant with a negative mass dimension, it has infinitely many free parameters, which means you can only use it below a given energy scale. Huh. Do you know of any videos that go into more depth? (My level is the "PBS Space Time" and Sabine Hossenfelder videos as I don't do this professionally).