Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China
Current neutrino oscillation data indicate that theta(13) is not strongly suppressed and theta(23) might have an appreciable deviation from pi/4, implying that the 3 x 3 neutrino mixing matrix V does not have an exact mu-tau permutation symmetry. We make a further study of the effect of mu-tau symmetry breaking on the democratic flavor distribution of ultrahigh-energy (UHE) cosmic neutrinos at a neutrino telescope, and find that it is characterized by vertical bar V-mu i vertical bar(2) - vertical bar V-tau i vertical bar(2) which would vanish if either theta(33) = pi/4 and theta(13) = 0 or theta(23) = pi/4 and delta = +/-pi/2 held. We observe that the second-order mu-tau symmetry breaking term (Delta) over bar may be numerically comparable with or even larger than the first-order term Delta in the flux ratios phi(T)(e) : phi(T)(mu) : phi(T)(tau) similar or equal to (1 - 2 Delta) : (1 + Delta + (Delta) over bar) : (1 + Delta - (Delta) over bar), if sin(theta(23) - pi/4) and cos delta have the same sign. The detection of the UHE De flux via the Glashow-resonance channel (nu) over bar (e)e -> W- -> anything is also discussed by taking account of the first- and second-order mu-tau symmetry breaking effects. (C) 2012 Elsevier B.V. All rights reserved.