Afterlife

[Alex K]

Heh


Of course I don't know which is the *correct* explanation because we lack the data to say. But to just give you one relatively simple explanation: The electrical dipole field of the neutron is undetectably small, and this fact seems odd in the Standard Model, where there is no reason why the corresponding free parameter should be so exceedingly small (though it could be zero without running into theoretical inconsistencies, this seems like an unlikely choice). To explain this fact completely unrelated to Dark Matter, one can promote this free parameter to a dynamical field called the Axion field by a not very complicated extension of the theory. One can then calculate that this field would retain residual energy density after the universe cools below the temperature where the strong force starts binding quarks and gluons. This residual energy density of the axion field would have precisely the correct properties to explain all effects connected to Dark Matter. The beauty of this approach is that it was not invented to explain Dark Matter but something else, and yet it also explains Dark Matter. Those are the best hypotheses. The Axion Dark Matter hypothesis has only been partially tested experimentally so far, but will be thoroughly tested by the next generations of so-called Axion Haloscopes, which could directly detect these hypothetical particles by converting them into microwaves in a powerful magnetic field.

Here's a currently running experiment of this type:

https://en.wikipedia.org/wiki/Axion_Dark...Experiment

Very interesting, thank you! So in this explanation, the condensation of quark-gluon plasma into hadrons "leaves behind" a certain amount of energy in a universe wide field and this is the 5x more dark matter influence on the rest of matter? Is there anything in this theory that directly predicts the 1 to 5 ratio?

Yes, that's roughly what would happen if that were the correct explanation: The energy in the axion field gets "frozen" once quantum chromodynamics develops a condensate. The 1:5 ratio is not exactly a completely fixed prediction, but it is plausible because the energy scale of the Axion field for which this ratio comes out correctly is very close to the energy scale which would explain the Neutrino masses and unification of forces, and these things *could* be related, but that's still speculative. Fortunately, the axion hypothesis is testable directly via detectors, so we don't have to rely on these somewhat shaky theoretical arguments.