Open Questions about Neutrinos Today

[ohwilleke]

This a confusing point for me. If neutrinos have mass, can they have chirality? And another point... Right handed neutrinos "don't exist" because they don't interact in EW theory. At least that is my understanding.

All SM fundamental fermions have chirtality.

 

[exponent137]

By end of year 2023 KATRIN will release their results (page 26): https://indico.in2p3.fr/event/29681.../attachments/76424/110930/04-TLasserre-v1.pdf
And then in 2025.

"next data release by end 2023 (<0.5 eV sensitivity)
target sensitivity: m < 0.2-0.3 eV by 2025"

 

[Vanadium 50]

I think KATRIN is a great experiment. But one must be careful to regard projections as estimates. They will release their results when they are ready. Sometimes it takes longer.

 

[exponent137]

News about KATRIN:
https://www.katrin.kit.edu/130.php#Anker0
https://pos.sissa.it/431/011/pdf

"Currently the combined analysis for measurement campaigns one to five is ongoing with an expected sensitivity of ∼ 0.5 eV."

But it seems that value 0,75 eV is a new one?
"The KATRIN collaboration has determined a neutrino mass limit in the sub-eV range. This is the current world-best limit from direct single β-decay measurements at 𝑚_𝜈 < 0.75 eV (90 % CL)"

 

[Vanadium 50]

So, we have two possibilities.

(A) The KATRIN experiment has chosen to update its results by presenting them at an obscure conference, with absolutely no explanation of what has changed. Indeed, the citation is to the older number.

(B) Some who gave the talk rounded a number differently in their presentation.

And you are asking us to go with Option A.

 

[exponent137]

So, we have two possibilities.

(A) The KATRIN experiment has chosen to update its results by presenting them at an obscure conference, with absolutely no explanation of what has changed. Indeed, the citation is to the older number.

(B) Some who gave the talk rounded a number differently in their presentation.

And you are asking us to go with Option A.

Yes, in principle, we are waiting for ∼ 0.5 eV. It was predicted at the end of the year 2023. But here, this prediction was repeated; maybe the update is close.

About 0,75 eV: I do not understand, but it is not as important as 0.5 eV. But I hope that this is more than rounding...

 

[Vanadium 50]

And you are asking us to go with Option A.

Yes,

Wow. Just wow.

 

[ohwilleke]

FWIW, "The KATRIN experiment has chosen to update its results by presenting them at an obscure conference"

I have no idea about this particular case, but this is often how new results are first spread, with publication following due to more rigorous publication than conference paper standards.

 

[Vanadium 50]

No they do not. They may announce preliminary results, but they are subject to change until submission to a journal, refereeing and publication.

They never, despite the claims of some non-physicists, release a result by putting a new number in the proceedings of an obscure conference, do not explain what has changed, and then cite the old published results.

Once again, wow.

 

[mfb]

* The finished analysis sets an upper limit of 0.75 eV.
* The ongoing analysis expects to set an upper limit of around 0.5 eV (assuming no signal), but the precise number will only be known once the analysis is done.

What's unclear?

The result of the ongoing analysis will be shown at a major conference and with a corresponding paper draft.

 

[Vanadium 50]

What's unclear?

The actual published paper rounds to 0.8 eV.

(It's more complicated than this, as the paper publishes multiple statistical procedures to indicate that no matter which one you pick, you get a similar number - which is useful information)