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comment by am_Unition

I know about the Dirac equation, but I've never really worked with it. It sounds like even if you assume that a chirality change or flavor violation occurred just before the particle would have emerged out of the south pole, there's no way that a sterile neutrino of an energy capable of producing the observed cascades/showers could travel through the entirety of the Earth. No? I'm not a particle guy.

    Fhtagn!

What? googles

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Devac  ·  2005 days ago  ·  link  ·  

    It sounds like even if you assume that a chirality change or flavor violation occurred just before the particle would have emerged out of the south pole.

When the problem is considered from a perspective of mass eigenstates, the flavour can change in a distance that's roughly proportional to 2E/|Δm²|where Δm² is a difference between squared masses/mass eigenvalues of transitioning neutrino. If I didn't make a mistake in my back of the envelope calculations, then at those energies it's at an order of tens of meters. EDIT: Scratch the last sentence. I used a bunch of possible values and considering the possible range for masses it's basically a meaningless figure. Sorry!

But when considering your question as a whole, I'm less convinced of my guesses. I only considered what could happen to neutrinos at that energy and what could explain it simply (thus considering neutrinos as Dirac and not Majorana particles). I hadn't yet tried to guesstimate my way through the whole problem.

    I'm not a particle guy.

Same here. I'm happy about it.

am_Unition  ·  2005 days ago  ·  link  ·  

2E/|Δm²| would be huge, right? E is probably around 10 TeV, and |Δm²| on the order of 0.1 eV/c² or less. There's gotta be some significant scaling factor/proportionality constant I'm missing.

Anyway, I dunno. One of the cruxes of my stance is trusting that the authors considered everything, which is a big scientific no-no. Btw, in the paper, everyone's from Penn State, which apparently has at least five different theory departments that overlap with particle physics. I found that pretty weird.

There's a professor at my school that was a coauthor on the Higgs Boson paper (easy when there's thousands of coauthors), but every week, ResearchGate informs me that he was "the most cited author in the department last week, with 153 new citations" or however many, and it's just like how can I compete with that? It's a broken metric when you have one guy that takes the title every week. So that's reason #58 that I hate high energy particle physics.

Devac  ·  2004 days ago  ·  link  ·  

Δm² is problematic because upper bound for sterile neutrino mass is something like 10^13 TeV and lower bound is "not exactly zero". Plus keep in mind that I cut everything down to obtain a first-order approximation and then used it on a wide range of values like a dumbass.

    Anyway, I dunno. One of the cruxes of my stance is trusting that the authors considered everything, which is a big scientific no-no.

Agreed.

am_Unition  ·  2004 days ago  ·  link  ·  

Yes, I'm so sorry, I very stupidly assumed that sterile neutrinos had the typical ~0.1 eV mass like that of active neutrinos.