rationalskepticism.org

The ANITA Anomalous Events as Signatures of a Beyond Standard Model Particle, and Supporting Observations from IceCube

The ANITA collaboration have reported observation of two anomalous events that appear to be εcr ≈ 0.6EeV cosmic ray showers emerging from the Earth with exit angles of 27◦ and 35◦, respectively. While EeV-scale upgoing showers have been anticipated as a result of astrophysical tau neutrinos converting to tau leptons during Earth passage, the observed exit angles are much steeper than expected in Standard Model (SM) scenarios. Indeed, under conservative extrapolations of the SM interactions, there is no particle that can propagate through the Earth with probability p > 10−6 at these energies and exit angles. We explore here whether “beyond the Standard Model” (BSM) particles are required to explain the ANITA events, if correctly interpreted, and conclude that they are. Seeking confirmation or refutation of the physical phenomenon of sub-EeV Earth-emergent cosmic rays in data from other facilities, we find support for the reality of the ANITA events, and three candidate analog events, among the Extremely High Energy Northern Track neutrinos of the IceCube Neutrino Observatory. Properties of the implied BSM particle are anticipated, at least in part, by those predicted for the “stau” slepton (τ ̃R) in some supersymmetric models of the fundamental interactions, wherein the stau manifests as the next-to-lowest mass supersymmetric partner particle.
...

We have demonstrated (Sec. II) that SM models can- not explain the ANITA anomalous events (AAEs) if they are correctly interpreted as εcr ≈ 0.6 EeV upgoing UHECR showers with exit angles of 27◦ to 35◦, or as we have termed them, Sub-EeV Earth-emergent Cosmic Rays (SEECRs).

Having excluded SM explanations at >5σ confidence, we have argued that the SEECR phenomenon, if con- firmed, can support a discovery-level claim of “beyond the Standard Model” (BSM) physics.
...