Theory 06/Physics, Cosmos & Matter /Neutrino physics
Neutrino Flavour Follows Turbulence
Flavour conversion is computed from a smooth profile. The real thing is churning.
Collective neutrino flavour conversion in a supernova is set by the turbulence spectrum rather than by the mean matter profile, so conversion should vary between otherwise similar explosions.
01The evidence
Neutrino flavour conversion depends sensitively on the matter profile, and simulations of the same progenitor with different turbulence produce different outcomes.
02The tension
Models use a spherically symmetric profile because it is tractable, and treat turbulence as a perturbation. The sensitivity suggests it is not a perturbation.
03The mechanism
Collective oscillations are sensitive to the phase accumulated along the path. Turbulence introduces phase noise that can decohere the collective mode, changing the conversion outcome.
That makes the turbulence spectrum the controlling variable, and predicts that the spread between similar events should be set by the spread in turbulence rather than by progenitor mass.
04What this is not
Smooth models treat turbulence as noise. This treats it as the control parameter.
05Predictions
- P1Conversion should vary with turbulence spectrum.
- P2Similar progenitors should differ.
- P3Phase noise should predict decoherence.
06Refutation
Conversion insensitive to turbulence would restore the smooth model.
07What it changes
It would change how supernova neutrino signals are interpreted.