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arXiv · 0804.3512

Implications of Leptonic Unitarity Violation at Neutrino Telescopes

Zhi-zhong Xing·Shun Zhou
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Abstract

A measurement of the ultrahigh-energy (UHE) cosmic neutrinos at a km^3-size neutrino telescope will open a new window to constrain the 3 x 3 neutrino mixing matrix V and probe possible new physics. We point out that it is in principle possible to examine the non-unitarity of V, which is naturally expected in a class of seesaw models with one or more TeV-scale Majorana neutrinos, by using neutrino telescopes. Considering the UHE neutrinos produced from the decays of charged pions arising from proton-proton and (or) proton-gamma collisions at a distant astrophysical source, we show that their flavor ratios at a terrestrial neutrino telescope may deviate from the democratic flavor distribution ϕ^T_e : ϕ^T_μ: ϕ^T_τ= 1 : 1 : 1 due to the seesaw-induced unitarity violation of V. Its effect can be as large as several percent and can serve for an illustration of how sensitive a neutrino telescope should be to this kind of new physics.

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Zhi-zhong Xing, Shun Zhou. 2008-07-04. Implications of Leptonic Unitarity Violation at Neutrino Telescopes. https://doi.org/10.1016/j.physletb.2008.07.011

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