Measurement of Atmospheric Neutrino Oscillations at 6-56 GeV with IceCube DeepCore

Area of Science:

• Particle Physics
• Astrophysics
• Cosmic Ray Physics

Background:

• Atmospheric neutrinos are produced by cosmic ray interactions in Earth's atmosphere.
• Neutrino oscillations are a quantum mechanical phenomenon where neutrinos change flavor.
• Understanding neutrino oscillations is crucial for particle physics and cosmology.

Purpose of the Study:

• To measure atmospheric neutrino oscillation parameters using IceCube-DeepCore data.
• To probe neutrino oscillations at energies (5.6–56 GeV) and baselines relevant to long-baseline experiments.
• To compare results with accelerator and reactor-based neutrino experiments.

Main Methods:

• Utilized three years of data from the IceCube Neutrino Observatory, focusing on the DeepCore infill array.
• Analyzed muon neutrino disappearance over various Earth-based baselines.
• Reconstructed neutrino energies and directions for events from the full sky.

Main Results:

• Measured the squared mass difference, Δm²₃₂ = 2.31⁺⁰.¹¹₋₀.₁₃ × 10⁻³ eV².
• Measured the atmospheric mixing angle, sin²θ₂₃ = 0.51⁺⁰.⁰⁷₋₀.⁰⁹, assuming normal neutrino mass ordering.
• Achieved precision comparable to established accelerator and reactor experiments.

Conclusions:

• The study provides precise measurements of atmospheric neutrino oscillation parameters.
• Results are consistent with existing data, reinforcing the Standard Model of particle physics.
• IceCube-DeepCore demonstrates capability for high-precision neutrino oscillation measurements using atmospheric neutrinos.