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Comment by mmastrac | Hacker News Reader

The article takes about 66% of its content before it actually explains why "Majorana" -- from the theoretician Ettore Majorana:

> So far the only known particles that are their own antiparticles are all bosons, particles that often carry force or mediate interactions, such as the photon, the pi-zero, or the Z. Ettore Majorana, a brilliant Italian theoretician who had a brief career in the 1920s and 30s but vanished mysteriously at the age of 32, was the first to propose that some fermions, particles of matter, might also be their own antiparticles.

https://en.wikipedia.org/wiki/Ettore_Majorana

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As is typical of LBL, they don’t also note the leading theories place majorana characteristics in a very small probability regime (particles are more and more demonstrating Dirac characteristics).

Demonstration of neutrino less double beta decay would prove majorana conjectures and point to fractures in the “standard model of physics” meaning new fundamental particles would be needed.

In my opinion whoever measures the CvB (cosmic neutrino background) will be more compelling because it isn’t a nullification result, it’s a result that would tell us far more about the Big Bang than we know now.

Neutrinos are hard to measure, have been the source of a lot of Nobel prizes!

Disclaimer: I use to work at lbl

The CvB is the holy grail. But it is an insanely challenging detection problem. I think the (multidecade?) PTOLEMY experiment is the only serious proposal, and particle physicists I knew were pretty skeptical it could actually pull it off for SM neutrinos.

https://arxiv.org/abs/1902.05508

Interesting, I read about neutrinos a while back https://arxiv.org/pdf/2304.14995

https://www.universetoday.com/13052/do-advanced-civilization... (I was reminded of this recently after watching the Three Body Problem - Tencent's version, interstellar quantum communication)

I used to work in neutrino physics, and I will consider myself lucky if I see a detection of the cosmic neutrino background in my lifetime (roughly the next 50 years).

If there's a prior in the community, my impression (as a neutrino physicist) is that if anything it's more toward Majorana than not, in the absence of evidence either way. It is surely nicer from a theory perspective, with a (seesaw) mechanism to help explain the very light neutrino masses, and lepton number violation that helps in the case for leptogenesis as an explanation for the universe's matter-antimatter asymmetry, etc. One way I think about it is that it's pretty interesting either way: Majorana demands physics beyond the Standard Model, while Dirac would seem to suggest that lepton number is more than an accidental symmetry of the Standard Model, implying some unknown quantum number. Meanwhile, many experimental searches for neutrinoless double beta decay go on, with many new/clever ideas to carve through the quite large allowed parameter space.

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