Physicists from the University of Massachusetts Amherst have proposed that the ultrahigh-energy neutrinos detected by the KM3NeT experiment may indicate an exploding “sub-extreme primordial black hole,” hinting at new physics beyond the Standard Model.
The KM3NeT experiment observed neutrinos with energies around 100 PeV, and IceCube detected five neutrinos exceeding 1 PeV. The explosion of a primordial black hole may account for these high-energy neutrinos. Image credit: Gemini AI.
Black holes are a well-understood phenomenon, originating when a massive star exhausts its fuel and undergoes a supernova explosion, resulting in a gravitational force strong enough to trap light. These traditional black holes are massive and relatively stable.
However, as noted by physicist Stephen Hawking in 1970, primordial black holes potentially formed not from stars, but from the universe’s primordial conditions following the Big Bang.
Theoretical in nature, primordial black holes are dense enough that light cannot escape. Surprisingly, they are expected to be significantly lighter than the black holes observed to date.
Hawking also demonstrated that when these primordial black holes heat up, they emit particles through a phenomenon known as Hawking radiation.
“The lighter the black hole, the hotter it becomes, leading to increased particle emission,” explained Dr. Andrea Tam, a physicist at the University of Massachusetts Amherst.
“As a primordial black hole evaporates, it becomes lighter and hotter, releasing even more radiation during the explosive process.”
“What our telescope detects is, in fact, Hawking radiation.”
“If we were to witness such an explosion, we would create a comprehensive catalog of all elementary particles in existence, confirming both known particles, like electrons and quarks, and those not yet observed, including hypothesized dark matter particles.”
In 2023, the KM3NeT experiment successfully detected this elusive neutrino—a result Dr. Tam and his team had anticipated.
However, a challenge arose from the IceCube experiment, which failed to record similar phenomena or approach even a fraction of KM3NeT’s findings.
If primordial black holes are prevalent and detonating often, why are we not inundated with high-energy neutrinos? What could explain this inconsistency?
Dr. Joaquín Iguazu Juan, a physicist at the University of Massachusetts Amherst, suggested, “We believe a primordial black hole with a ‘dark charge’, termed a quasi-extreme primordial black hole, could bridge this gap.”
“Dark charge mimics standard electric force but features a heavy hypothesized electron, the dark electron.”
Dr. Michael Baker, also from UMass Amherst, remarked, “Our dark charge model is complex but may provide a more accurate depiction of reality.”
“It’s remarkable that our model explains this previously unexplainable phenomenon.”
Dr. Tam added, “Dark-charged primordial black holes possess unique properties that differentiate them from simpler primordial black hole models, allowing us to resolve all conflicting experimental data.”
The research team is optimistic that their dark charge model not only elucidates neutrino observations but also addresses the enigma of dark matter.
“Observations of galaxies and the cosmic microwave background imply the existence of some form of dark matter,” explained Baker.
“If our dark charge hypothesis holds, it could suggest a considerable number of primordial black holes, aligning with other astrophysical observations and accounting for the universe’s missing dark matter,” Dr. Iguazu-Juan stated.
“The detection of high-energy neutrinos represents a significant breakthrough,” remarked Baker.
“It opens a new window into the universe, enabling us to empirically verify Hawking radiation, gather evidence of primordial black holes, and explore particles beyond the Standard Model, while inching closer to solving the dark matter mystery.”
For more details, see the findings published in Physical Review Letters.
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Michael J. Baker and colleagues. We explain the PeV neutrino flux in KM3NeT and IceCube with quasi-extreme primordial black holes. Physics. Pastor Rhett, published online December 18, 2025. doi: 10.1103/r793-p7ct
Source: www.sci.news
