Cosmic mystery of the impossibly high-energy neutrino solved by "dark charge" model of black holes :
In 2023, a subatomic particle called a neutrino crashed into Earth with an impossibly huge amount of energy. In fact, no known sources anywhere in the universe can produce that much energy, 100,000 times more than the highest-energy particle ever produced by the Large Hadron Collider, Earth's most powerful particle accelerator. However, a team of physicists at the University of Massachusetts Amherst recently hypothesized that something like this could happen when a special kind of black hole, called a quasi-extremal primordial black hole, explodes.
Black holes exist, and we have a good understanding of their life cycle: an old, large star runs out of fuel, implodes in a massively powerful supernova, and leaves behind an area of spacetime with such intense gravity that nothing, not even light, can escape. These black holes are incredibly heavy and are essentially stable.
But, as physicist Stephen Hawking pointed out in 1970, another kind of black hole – a primordial black hole – could be created not by the collapse of a star, but from the universe's primordial conditions shortly after the Big Bang. Primordial black holes exist only in theory so far. And, like standard black holes, they're so massively dense that almost nothing can escape them ... which is what makes them black. However, despite their density, primordial black holes could be much lighter than the black holes we have so far observed. Furthermore, Hawking showed that primordial black holes could slowly emit particles via what is now known as Hawking radiation if they got hot enough.
Andrea Thamm, co-author of the new research and assistant professor of physics at UMass Amherst, said:
The lighter a black hole is, the hotter it should be and the more particles it will emit. As primordial black holes evaporate, they become ever lighter, and so hotter, emitting even more radiation in a runaway process until explosion. It's that Hawking radiation that our telescopes can detect.
If such an explosion were to be observed, it would give us a definitive catalog of all the subatomic particles in existence. That would include the ones we have observed, such as electrons, quarks and Higgs bosons. And also the ones that we have only hypothesized, like dark matter particles, as well as everything else that is, so far, entirely unknown to science. The UMass Amherst team has previously shown that such explosions could happen with surprising frequency – every decade or so – and if we were to pay attention, our current cosmos-observing instruments could register these explosions.
Then, in 2023, an experiment called the KM3NeT Collaboration captured that impossible neutrino. It was exactly the kind of evidence the UMass Amherst team hypothesized we might soon see.
[...] Co-author Joaquim Iguaz Juan, a postdoctoral researcher in physics at UMass Amherst, said:
We think that primordial black holes with a 'dark charge' – what we call quasi-extremal primordial black holes – are the missing link.
The dark charge is essentially a copy of the usual electric force as we know it. But it includes a very heavy, hypothesized version of the electron, which the team calls a dark electron.
Co-author Michael Baker, an assistant professor of physics at UMass Amherst, said:
There are other, simpler models of primordial black holes out there. Our dark-charge model is more complex, which means it may provide a more accurate model of reality. What's so cool is to see that our model can explain this otherwise unexplainable phenomenon.
Thamm added:
A primordial black hole with a dark charge has unique properties and behaves in ways that are different from other, simpler primordial black hole models. We have shown that this can provide an explanation of all of the seemingly inconsistent experimental data.
Journal Reference: Baker, Juan, Symons, and Thamm, Explaining the PeV Neutrino Fluxes at KM3NeT and IceCube with Quasiextremal Primordial Black Holes, Phys. Rev. Lett., 136, 2026. https://doi.org/10.1103/r793-p7ct
(Score: 3, Interesting) by JoeMerchant on Sunday February 22, @03:46AM
Seems like every time we advance to the next level of "fire" some of us get existential dread that it will burn out of control, destroying the earth in cataclysm due to our reckless dabbling in "unnatural" energies.
The global atmosphere, or oceans, or both were going to burn in a chain reaction set off by hydrogen bomb testing...
The world was going to consume itself into a black hole due to the LHC's search for Higgs' Boson due to the use of "higher energies than ever before..."
The latest Superman movie leaned hard into world-tearing disasters from such interdimensional tampering.
At least scientists can now point to our detection of this doubtless one of trillions of such high energy particles zipping through our planet without ending it (yet) after billions of years of such encounters.
But, if Spock ever drops the red matter...
🌻🌻🌻🌻 [google.com]
(Score: 2, Interesting) by shrewdsheep on Sunday February 22, @09:00PM (1 child)
I thought the definition of a dark hole is that gravity is strong enough to let nothing escape. Any explosions inside the black hole, which seem possible, should therefore only explode inwards. Whatever new force/particle is made up, what would be the mechanism to overcome gravity?
(Score: 4, Interesting) by KritonK on Tuesday February 24, @09:36AM
Black holes emit Hawking radiation [wikipedia.org], thus slowly losing mass. Hawking described it in layman's terms in one of his books, which was much more understandable than the Wikipedia article. If I remember correctly, under certain circumstances, energy from the black hole gets converted into particle-antiparticle pairs outside its event horizon, with one such particle falling into the black hole and the other particle escaping, which to an outside observer would appear as if the black hole had emitted that particle.
In any case, this amount of lost mass is negligible for massive black holes created by the collapse of stars, but can be significant for primordial black holes having small mass. At some point, the mass of the primordial black hole will thus become smaller than the amount required to hold the black hole together, and the black hole blows up. TFA suggests that the 2023 event may have been one such explosion.