The Standard Model of Particle Physics is one of the pinnacles of human ingenuity. It describes the world of particles and their interactions and its predictions have been confirmed time and time again. It is also limited. And we have been pulling at those threads for a while, trying to see what lies beyond.
Research from 2018 showed a couple of events detected by the Antarctic Impulsive Transient Antenna (ANITA) experiment that couldn’t be reconciled with the standard model. A new study adds to those detections as well as a third one from ANITA by checking them against data from the IceCube Neutrino Observatory. And it seems there could be some very exciting explanations for the anomalies.
ANITA and IceCube look for the same type of particles, ultra-high-energy cosmic neutrinos, but use different methods. Neutrinos are particles with no electric charge and a tiny mass. These two properties allow them to easily move through a planet unscathed. If you hold up your thumb, about 100 billion neutrinos will pass through your thumbnail every second.
Given just how many there are, occasionally a neutrino will hit the nucleus of an atom releasing light and a cascade of other particles. IceCube detectors embedded in the Antarctic ice look for flashes caused by neutrino collisions. ANITA, meanwhile, is up on an aerostatic balloon looking for the shower cascade coming from the ground after the neutrinos, having crossed a planet, end up colliding with something in the ice.
The three events detected, from 2006, 2014, and 2015, are extremely energetic. The first two had energy comparable to a coin falling from a table, which is huge considering that these are minuscule subatomic particles. The third one's energy was much greater. The team poured over IceCube's data but didn’t spot any detections, which makes the anomalies even more anomalous.
And here comes the kicker. According to the analysis, which is yet to be peer-reviewed but is available on arXiv, the detections are inconsistent with astrophysical interpretations. No supernova or neutron star collisions appear to be behind these unusual events.
The events are consistent with certain physics beyond the Standard Model, including certain models to explain dark matter. The team now plans to constrain the possible parameters for these models in future work. The researchers are also planning to conduct more investigations to ensure that the anomalies truly had the incredible properties ANITA detected.
A new paper about ANITA’s data is coming out later this year, so we will just have to wait to see what comes out of that.
[H/T: New Scientist]