The best model of particle physics is now chock-full as it tries to explain all the peculiarities in the Universe. It appears more prone than ever to explode, due to a series of weird occurrences in Antarctica.
Peculiar results from lab experiments imply waves of spectral new species of neutrinos aside from the three depicted in the Standard Model. Also, the Universe is abundant in dark matter too, which is something no particle in this Standard Model can clarify.
However, new appealing evidence might someday link those dim strands of information together. For already three times since 2016, ultra-high-energy particles have shown up at the surface of the ice in Antarctica, canceling out the detectors in the Antarctic Impulsive Transient Antenna (ANITA) project, a device hanging from a NASA balloon above the ice.
These events, together with extra particles identified at the Antarctic neutrino observatory IceCube, do not label under the expected behavior of the Standard Model particles. The particles rather look like ultra-high-energy neutrinos, but again, these types of neutrinos should not have the ability to pass through the Earth. That implies that some other type of particle, one that has never been encountered before, is appearing into the atmosphere.
The Possibilities of Survival are Incredibly Low
In a new study, a team of physicists involved in the IceCube expedition has thrown massive doubt on one of the last standing Standard Model suggestions for these particles, namely cosmic accelerators, which are massive neutrino guns concealing themselves in space that would regularly expel powerful neutrino bullets at Earth.
Even so, ultra-high-energy neutrinos from deep space are not similar to the low-energy particles. They are much rarer than the latter and have broader ‘cross-sections,’ which means they are more prone to crash with other particles as they travel through them.
The possibility of an ultra-high-energy neutrino getting through Earth in good shape is so low that it would never have actually to be considered. Numerous ultra-high-energy neutrinos have appeared from the interactions of cosmic rays with the cosmic microwave background (CMB). Every now and then, those cosmic rays engage with the CMB in just the correct way to expel high-energy particles at our planet.
This is what is known as ‘flux,’ and it happens all over the sky. However, both ANITA and IceCube have already calculated that the cosmic neutrino flux seems like, to each of their sensors. The result shows that the flux doesn’t really generate sufficient high-energy neutrinos that you’d get to identify a neutrino expelled from Earth at the detectors even once.
Nothing Turned Up
Anastasia Barbano, a physicist from the University of Geneva who is working on IceCube, said: “If the events detected by ANITA belong to this diffuse neutrino component, ANITA should have measured many other events at other elevation angles.”
However, theoretically, there could have been ultra-high-energy origins beyond the flux, the physicist said.
“If it is not a matter of neutrinos produced by the interaction of ultra-high-energy cosmic rays with the CMB, then the observed events can be either neutrinos produced by individual cosmic accelerators in a given time interval” or some unknown Earthly source,” Barbano said.
According to Barbano, ANITA only detects the most extreme high-energy neutrinos, and if the traveling particles were cosmic-accelerator-powered neutrinos from the Standard Model, then the ray should have appeared with a multitude of lower-energy particles that would have closed off IceCube’s lower-energy sensors.
“We looked for events in seven years of IceCube data,” Barbano said, but no important battery of cosmic neutrino guns that would generate these traveling particles showed up. The team’s results do not entirely remove the probability of an accelerator cause in the cosmos. But they do ‘severely constrain’ the level of probabilities, getting rid of the most logical scenarios including cosmic acceleration and other less-plausible ones.
“The message we want to convey to the public is that a Standard Model astrophysical explanation does not work no matter how you slice it.”
“We have to wait for the next generation of neutrino detectors,” Barbano said.
The study has now yet been reviewed. It was issued in the arXiv database on January 8th.