Michael V said:
dv said:
It’s only been a couple of years since they first observed neutrino oscillation. Have to admit I’m not exactly read up, but the difference between their rest masses is very small in absolute terms.
Couldn’t the same be said for all subatomic particles? I mean even the largest subatomic particle has a mass of two fifths of five eighths of bugger all.
This might answer my question, if I could understand it. https://en.wikipedia.org/wiki/Neutrino_oscillation#Theory
“As a neutrino superposition propagates through space, the quantum mechanical phases of the three mass states advance at slightly different rates, due to the slight differences in their respective neutrino masses. This results in a changing superposition mixture of mass eigenstates as the neutrino travels; but a different mixture of mass eigenstates corresponds to a different mixture of flavor states … In contrast, due to their larger masses, the charged leptons (electrons, muons, and tau leptons) have never been observed to oscillate. No analogous mechanism exists in the Standard Model that would make charged leptons detectably oscillate. Where the charged lepton is emitted in a unique mass eigenstate, the charged lepton will not oscillate, as single mass eigenstates propagate without oscillation.”
The word I’m struggling with here regarding electrons changing to muons is “detectably”. Does this mean it can’t exist or can exist? And if it can exist, could it happen quickly in the early stages of the Big Bang?
The application for cosmology would be that if such oscillations exist then particles changing their fundamental nature could occur without any recourse to either supersymmetry or any other GUT extension beyond the standard model.
For instance, if oscillations between particles and antiparticles were possible and rapid in the early Big Bang then the freezing out of the oscillation phase could explain why our universe contains matter rather than equal amounts of matter and antimatter. And the deviation from equality could be very much larger with a frozen oscillation than could be explained solely by the matter-antimatter asymmetry of kaons and b mesons.
I see now that the question of electrons changing into muons has been a common topic for scientific papers. eg. Do charged leptons oscillate
“Ever since the idea of neutrino oscillations was put forward, the question of whether charged leptons can also undergo oscillations has been vividly discussed. While most of the authors conclude that such oscillations are not possible for one reason or another, others come to the opposite conclusion”
So it’s still an open question, and one that physicists are very opinionated about.
“Do e±, μ± and τ± oscillate into each other? The answer to this question is the immediate ‘no’. The reason for this is that mass eigenstates evolve by simply picking up phase factors whose moduli are always equal to unity.”
So that settles it, only …
“It should be noted that the same argument applies to neutrinos. Can we imagine a situation when one creates a coherent superposition of e, μ and τ and then also detects their coherent superposition rather than individual mass-eigenstate charged leptons? If this were possible, one would be able to observe oscillations between such mixed charged lepton states”.
So it’s not settled.
“What is the origin of the disparity between neutrinos and charged leptons? One might suspect that this disparity comes about because of the enormous difference between the masses of charged leptons and neutrinos, and this is indeed the case … if this were the case then charged leptons would oscillate into each other, while neutrinos would not be able to oscillate. We know that in reality neutrinos do oscillate, so what is wrong with this apparently consistent possibility? To make the problem look even worse …’
I think it’s time for me to leave off looking at that paper.
From another source: “No, lepton oscillation does not happen, because we define e, µ and τ to be the mass eigenstates of the charged leptons.”
That seems to me a wrong definition. e, µ and τ should be defined to be the flavour eigenstates not the mass eigenstates. There is a difference.