Neutrino Telescopes as a Probe of Broken μ-τ Symmetry

It is known that neutrino oscillations may map φe : φμ : φτ = 1 : 2 : 0, the initial flavor ratios of ultrahigh-energy neutrino fluxes produced from a distant astrophysical source, into φe : φ D μ : φ D τ = 1 : 1 : 1 at the detector of a neutrino telescope. We remark that this naive expectation is only valid in the μ-τ symmetry limit, in which two neutrino mixing angles satisfy θ13 = 0 and θ23 = π/4. Allowing for the slight breaking of μ-τ symmetry, we find φe : φ D μ : φ D τ = (1 − 2∆) : (1 + ∆) : (1 + ∆) with ∆ characterizing the combined effect of θ13 6= 0 and θ23 6= π/4. Current neutrino oscillation data indicate −0.1 ∼ ∆ < ∼ +0.1. We also look at the possibility to probe ∆ by detecting the νe flux of Eν e ≈ 6.3 PeV via the Glashow resonance channel νee → W − → anything. PACS number(s): 14.60.Lm, 14.60.Pq, 95.85.Ry Typeset using REVTEX ∗E-mail: [email protected]