  The IceCube experiment has recently reported the observation of 28
high-energy (> 30 TeV) neutrino events, separated into 21 showers and 7 muon
tracks, consistent with an extraterrestrial origin. In this letter we compute
the compatibility of such an observation with possible combinations of neutrino
flavors with relative proportion (alpha_e:alpha_mu:alpha_tau). Although the
7:21 track-to-shower ratio is naively favored for the canonical (1:1:1) at
Earth, this is not true once the atmospheric muon and neutrino backgrounds are
properly accounted for. We find that, for an astrophysical neutrino E^(-2)
energy spectrum, (1:1:1) at Earth is disfavored at 81% C.L. If this proportion
does not change, 6 more years of data would be needed to exclude (1:1:1) at
Earth at 3 sigma C.L. Indeed, with the recently-released 3-year data, that
flavor composition is excluded at 92% C.L. The best-fit is obtained for (1:0:0)
at Earth, which cannot be achieved from any flavor ratio at sources with
averaged oscillations during propagation. If confirmed, this result would
suggest either a misunderstanding of the expected background events, or a
misidentification of tracks as showers, or even more compellingly, some exotic
physics which deviates from the standard scenario.
