Work

Potential divergence in tracing μ and τ flavors of astrophysical neutrinos

Year: 2026

Type: article

Abstract: We derive general formulas for three flavor fractions ( η e , η μ , η τ ) of the high-energy neutrinos originating from a remote astrophysical source by using their flavor ratios ( f e , f μ , f τ ) observed at a neutrino telescope, and diagnose a potential divergence associated with η μ and η τ as an unavoidable consequence of the μ − τ interchange symmetry exhibiting in the 3 × 3 lepton flavor mixing matrix U . We present a complete set of analytical expressions for ( η e , η μ , η τ ) as functions of two typical μ − τ symmetry breaking parameters in the standard parametrization of U , and apply it to the recent IceCube all-sky neutrino flux data ranging from 5 TeV to 10 PeV in the assumption that the relevant sources have a common flavor composition. We also explain why only η e and η μ + η τ can be extracted from a precision measurement of f e and f μ = f τ in the exact μ − τ flavor symmetry limit.

Source: Nuclear Physics B

DOI: 10.1016/j.nuclphysb.2026.117444

Author: Zhi-zhong Xing

Institutions: Chinese Academy of Sciences, Peking University, Institute of High Energy Physics, University of Chinese Academy of Sciences

Language: English

Topic: Neutrino Physics Research

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: diamond

Funders: National Natural Science Foundation of China, Institute of High Energy Physics, High Energy Physics

Awards: G1421044790, G8923864342, G894152365