Eur. Phys. J. C (2025) 85: 1481
https://doi.org/10.1140/epjc/s10052-025-15207-5

Regular Article - Theoretical Physics

Searching for pseudo-dirac neutrinos from astrophysical sources in IceCube data

¹ Centre for Astro-Particle Physics (CAPP) and Department of Physics, University of Johannesburg, PO Box 524, Auckland Park, 2006, South Africa
² Instituto de Física de São Carlos, Universidade de São Paulo (USP), Av. Trabalhador São Carlense 400, São Carlos, São Paulo, Brazil
³ Department of Physics, The George Washington University, 20052, Washington, DC, USA
⁴ National Institute for Theoretical and Computational Sciences (NITheCS), Private Bag X1, Matieland, South Africa

^a This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 20 January 2025
Accepted: 14 December 2025
Published online: 30 December 2025

Abstract

We analyze IceCube public data from its IC86 configuration, namely PSTracks event selection, to search for pseudo-Dirac signatures in high-energy neutrinos from astrophysical sources. Neutrino flux from astrophysical sources is reduced in the pseudo-Dirac scenario due to the conversion of active-to-sterile neutrinos as compared to the neutrino oscillation scenario of only three active neutrinos over astrophysical distances. We fit IceCube data using astrophysical flux models for four point-like sources in both scenarios and constrain the active-sterile mass-square-difference in the absence of any evidence for the pseudo-Dirac scenario. We present the exclusion regions for the common mass-squared difference $\delta m^2$, inducing active-sterile oscillations, for all three neutrino flavors. This includes results from individual sources as well as from a stacking analysis that combines data from the four sources. Our findings indicate that the exclusion region is $\delta m^2\in [2.1\times {10}^{-21}-2.0\times {10}^{-16}]$ eV$_{}^2$ with $\ge 90\%$ confidence level (CL) significance for neutrino energies ranging from 0.5 TeV to 1 PeV. When we extend the energy range down to 0.1 TeV, the exclusion region broadens to $\delta m^2\in [1.1\times {10}^{-21}-3.0\times {10}^{-16}]$ eV$_{}^2$ at $\ge 90\%$ CL.