10 March 2026 – We present a new paper with the title ‘Atmospheric neutrino constraints on Lorentz invariance violation with the first six detection units of KM3NeT/ORCA’.
In the paper, we describe our search for the violation of isotropic Lorentz invariance using 1.4 years of atmospheric neutrino data collected with ORCA6 – the first six detection units of the ORCA detector.
Atmospheric neutrinos offer a powerful option to test Lorentz invariance, a fundamental symmetry underlying all of modern physics. Using data collected with the ORCA6 neutrino telescope, we searched for deviations from standard neutrino oscillations that could arise from a violation of this symmetry. While no violation was observed, our analysis places new constraints on a widely studied model of Lorentz invariance violation (LIV).
With ORCA6 we established the first upper limits on isotropic diagonal LIV coefficients in the neutrino sector that do not rely on assumptions about the initial astronomical neutrino flavour ratios. The model-independent approach enhances the robustness and general applicability of the constraints obtained.
The paper has been submitted to Journal of Cosmology and Astroparticle Physics and is available as a preprint at arXiv: 2603.04264
In the picture a comparison of our results with those from approximately 12 years of Super-Kamiokande data and a two-year IceCube analysis based on atmospheric neutrinos. Our analysis provides competitive results despite the relatively small size of ORCA6 and the short time of operation in this configuration.
