I High energy tritons

[snorkack]

Cosmic rays are well attested to include particles with energies above 100 EeV. Three most energetic rays observed have been OMG particle (320 EeV, in 1991), an unnamed particle in 2001 (280 EeV) and Amaterasu particle in 2021 (240 EeV).
Pierre Auger observatory has seen 100 particles over 78 EeV:
https://iopscience.iop.org/article/10.3847/1538-4365/aca537
How often is the actual charge and mass of a cosmic ray identified?
t is unstable... with half-life 12 y at rest frame.
Suppose we had a t with 3 PeV energy. That would mean half-life 12 million years... quite plausible time to reach from a cosmic ray source in another galaxy to Earth.
Do cosmic ray detectors commonly make the identification of charge to distinguish radioactive cosmic rays from their daughters, like t/³He, ¹⁰Be/¹⁰B, ¹⁴C/¹⁴N?
If yes, how do the abundances of radioactive cosmic rays compare to their daughters, as function of energy and towards the high energy limit?
Also, t emits low energy antineutrinoes. Maximum energy 18 keV, average energy less.
If you had a 3 PeV t decay and emit the antineutrino backwards (no reason why not, it is not feeling any ether or absolute space to prefer any direction) then the antineutrino at 18 keV relative to t would be redshifted to 18 meV... if massless. But the region of meV/ceV is where the differences of neutrino rest masses lie!
Are cosmic ray antineutrinoes often redshifted into wrong helicity/sterile antineutrinoes?

 

[phyzguy]

The Auger observatory has determined that the highest energy cosmic rays are more massive nuclei, as heavy as iron. See figure 2 in this paper.

 

[mfb]

You need an extremely high energy of an uncommon nucleus, and you need the decay to emit the neutrino into an extremely narrow range. I wouldn't exactly call this "often".

 

[ohwilleke]

Cosmic rays are well attested to include particles with energies above 100 EeV. Three most energetic rays observed have been OMG particle (320 EeV, in 1991), an unnamed particle in 2001 (280 EeV) and Amaterasu particle in 2021 (240 EeV).
Pierre Auger observatory has seen 100 particles over 78 EeV:
https://iopscience.iop.org/article/10.3847/1538-4365/aca537
How often is the actual charge and mass of a cosmic ray identified?
t is unstable... with half-life 12 y at rest frame.
Suppose we had a t with 3 PeV energy. That would mean half-life 12 million years... quite plausible time to reach from a cosmic ray source in another galaxy to Earth.

It is worth recalling that the half-lives of particles are calculated in the reference frame of the particle and not the observer. Particles like these are, by definition at these energies, traveling at relativistic speeds often very, very close to the speed of light. So, the half-life in the observer's frame of reference has to be adjusted for special relativistic time dilation and the adjustment is a significant one.

It is hard to follow the OP analysis, which is a bit scattered, to see to what extent this is being considered.

Are cosmic ray antineutrinoes often redshifted into wrong helicity/sterile antineutrinoes?

This never happens in the Standard Model. There is also no observational evidence to support this hypothesis.

 

[snorkack]

It is worth recalling that the half-lives of particles are calculated in the reference frame of the particle and not the observer. Particles like these are, by definition at these energies, traveling at relativistic speeds often very, very close to the speed of light. So, the half-life in the observer's frame of reference has to be adjusted for special relativistic time dilation and the adjustment is a significant one.
It is hard to follow the OP analysis, which is a bit scattered, to see to what extent this is being considered.

Requoting the relevant part:

t is unstable... with half-life 12 y at rest frame.
Suppose we had a t with 3 PeV energy. That would mean half-life 12 million years

For any speed v whatever:
(E+mc²)=mc²*√(c²/(c²-v²))
t_v=t₀*√(c²/(c²-v²))

It is the same expression √(c²/(c²-v²)) in both formulae.
When a particle is travelling at speed very close to speed of light, √(c²/(c²-v²))>>1, and thus E+mc²>>mc² and E≈E+mc²
What I did not spell out but assumed implied: the mass of t≈3 GeV (to the same approximation that half-life at rest frame is approximately 12 y), so in an observer frame where E≈3 PeV, √(c²/(c²-v²))≈1*10⁶, so half-life is approximately 12 million years.

This never happens in the Standard Model. There is also no observational evidence to support this hypothesis.

Then how does the standard model handle Lorentz transition?
In special relativity, for any finite v, it can be made arbitrarily small OR reverse direction, OR be made exactly zero by suitable Lorentz transition.
Neutrino oscillations give the 2 rest mass differences of the neutrino mass eigenstates as 2440 and 75,3 meV². Which means that one mass eigenstate must have rest mass at least 49,4 meV and the second at least 8,7 meV.
The rest mass of the third eigenstate might be arbitrarily small or even exactly zero. The latter is, however, not a popular guess.
Since Lorentz boost of 10⁶ commonly occurs in real life observations (high energy cosmic ray tail) and emission of antineutrinos with energy in low keV also commonly occurs in real life observations (beta decay of t and ¹⁸⁷Re), it is a logical question to ask what happens if a low energy neutrino is redshifted.
Normal Lorentz transitions say that reversing direction of movement by change of frame does not reverse spin, and indeed it is possible to redshift a particle with nonzero mass int a stationary particle, which still has spin.
Standard Model is claimed to state that opposite helicity neutrino is somehow fundamentally nonexistent, not merely hard to produce and hard to detect.
Then what does Lorentz transition of a low energy neutrino do in Standard Model? Somehow avert the normal change of helicity with velocity?
Of course it is likely to be very hard to actually observe nonrelativistic neutrinos, because their cross-section, in Standard Model, keeps dropping with energy - even if they keep their correct helicity. But combination of other observations suggests that a small number of slow neutrinos should exist!