High-energy neutrinos from IceCube

[bcrowell]

http://arxiv-web3.library.cornell.edu/abs/1311.5238

"Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube Detector"

We report on results of an all-sky search for high-energy neutrino events interacting within the IceCube neutrino detector conducted between May 2010 and May 2012. The search follows up on the previous detection of two PeV neutrino events, with improved sensitivity and extended energy coverage down to approximately 30 TeV. Twenty-six additional events were observed, substantially more than expected from atmospheric backgrounds. Combined, both searches reject a purely atmospheric origin for the twenty-eight events at the 4σ level. These twenty-eight events, which include the highest energy neutrinos ever observed, have flavors, directions, and energies inconsistent with those expected from the atmospheric muon and neutrino backgrounds. These properties are, however, consistent with generic predictions for an additional component of extraterrestrial origin.

Judging from newspaper accounts, a lot of physicists seem very excited by this paper. Can anyone offer any further insight? Are the present results hard to explain theoretically? Are there specific questions that can be answered by IceCube?

 

[fzero]

There was some discussion earlier in this thread. I will have to look at the present paper to see if there's any evidence for deviation from the expected known-physics background for extraterrestrial neutrinos that was discussed in that thread.