Speaker
Description
Author: Dibya S. Chattopadhyay
Co-author: Vedran Brdar
Abstract: The KM3NeT collaboration recently reported the observation of KM3-230213A, a neutrino event with an energy of 220 PeV. The absence of any
PeV events in IceCube, despite its larger effective area and longer data-taking period, suggests an anomaly, with a tension quantified between approximately ~2 and 3.5, depending on the assumed source model. This implies a possible new physics origin for the event KM3-230213A.
Meanwhile, the anomalous upgoing events detected by the ANITA experiment, with energies near 1 EeV and arrival angles implying traversal through thousands of kilometers of Earth, similarly hint at a possible origin involving new physics in the neutrino sector.
We investigate two mechanisms that could simultaneously account for both anomalies: one in which a new matter potential induces a resonance in sterile-to-active neutrino transitions, and another involving off-diagonal neutrino non-standard interactions. Using the arc lengths traversed by the ANITA events, we identify the relevant parameter space and explore how matter-enhanced oscillations between the sterile and active sectors may help explain both the ANITA and KM3NeT observations. Overall, we examine the possibility that recent ultra-high-energy neutrino observations have already observed physics beyond the Standard Model.
