Lorentz Violation in Neutrino Oscillations Using IceCube Atmospheric Neutrino Interferometry

Abstract

Lorentz invariance is a fundamental symmetry of spacetime underpinning the Standard Model (SM) and our understanding of high-energy phenomena in particle physics. However, beyond the quantum gravity scale, we expect the SM to be replaced with a more fundamental, covariant theory giving a quantum description of gravity. The effective theory arising from this theory can break Lorentz invariance and thus predicts observables that exhibit low-energy manifestations of Lorentz violation. In particular, these observables could be a subleading contribution to neutrino oscillations and could therefore explain anomalous flavor measurements. The Standard Model Extension (SME) formalism describing such an effective theory predicts terms whose characteristic oscillation length becomes significant at atmospheric neutrino energies accessible by the IceCube Neutrino Observatory. We descibe past measurements and efforts to extend these using ten years of data along with a new energy reconstruction to study $\nu_{\mu}$ disappearance.