IceCube might've caught 7 exotic 'ghost particles' as they pierced through Earth

[Admin]

The IceCube facility may have caught evidence of seven elusive ghosts. There is nothing supernatural about them, however. They're "ghost particles," or neutrinos, that come from powerful cosmic sources.

IceCube might've caught 7 exotic 'ghost particles' as they pierced through Earth : Read more

 

[danR]

"Neutrinos are charge-less and nearly mass-less particles that blast through the cosmos at speeds approaching that of light. Oddly enough, because of those parameters, neutrinos barely interact with anything."

That would be a reason why photons would barely interact with anything. Which they do, and fairly vigorously sometimes.

Neutrinos are mainly prone to weak-field interactions, which opportunities they rarely stumble on, and to a teeny extent, gravitational fields.

 

[Torbjorn Larsson]

The 1 in 3.5 million likelihood is a more than 5 sigma detection! So it is indeed confirmation of astrophysical and not only solar (or other sources) neutrinos.

Speaking of which, the 2024 eROSITA X-ray sky survey cosmology paper has set a tightest limit on total neutrino mass. And disfavor the inverted mass hierarchy at 2 sigma. (This potentially means mass oscillating neutrinos can break the universe matter/antimatter asymmetry by leptogenesis. It is favored by 2 sigma - at normal mass ordering - by the NOvA neutrino experiment.)

Now if we can only figure out a way to detect the cosmological neutrino background...

Neutrinos are mainly prone to weak-field interactions, which opportunities they rarely stumble on, and to a teeny extent, gravitational fields.

Indeed. I have seen a cosmological paper study the 0.2 % by mass neutrino "dark matter" potential component - not quite the remaining massier ("cold") dark matter - to conclude that we can safely ignore it for first order effects. It smears weak lensing observations a bit, but not significantly so.

 

[Cdr. Shepard]

Speaking of which, the 2024 eROSITA X-ray sky survey cosmology paper has set a tightest limit on total neutrino mass. And disfavor the inverted mass hierarchy at 2 sigma. (This potentially means mass oscillating neutrinos can break the universe matter/antimatter asymmetry by leptogenesis. It is favored by 2 sigma - at normal mass ordering - by the NOvA neutrino experiment.)

Thanks for the observations Torbjorn. Could you explain the bolded portion for me?

I find particle physics absolutely fascinating but much of it is still ostensibly black magic to me and my lack of study in the field. Please help, o wise one.