Deciphering the cosmic muon neutrino flux in IceCube

The IceCube Collaboration is now accumulating more statistics in the search for the sources of very high energy neutrinos, but also to learn more about their nature. In a new study, submitted this week to the Astrophysical Journal, the collaboration reports a substantially improved observation of the diffuse muon neutrino flux in the Northern Hemisphere using six years of IceCube data with about a tenfold increase in statistics. Once more, a clear astrophysical contribution has been found, which at the highest energies excludes a purely atmospheric origin at the 5.6 sigma level. Also, the accuracy of the measurement of the spectral properties has been improved.
[…]

Read More »


IceCube search for cosmogenic neutrinos favors heavy nuclei cosmic-ray sources

The IceCube Collaboration has made public today that a new search for cosmogenic neutrinos resulted in two very high energy neutrinos. These neutrinos, which are found to be of astrophysical origin with a 92.3% probability, include the highest energy neutrino detected to date. While of astrophysical origin, the energy of these neutrinos does not match the expectation for a cosmogenic neutrino flux. The lack of evidence for such events in a search of seven years of IceCube data places very strong constraints on the sources of UHECR. Proton-dominated sources are greatly disfavored, and testing mixed and heavy nuclei cosmic-ray sources will require much bigger instruments, such as an extension of IceCube or radio Askaryan neutrino detectors. These results have been submitted yesterday to Physical Review Letters. […]

Read More »


IceCube aims for neutron astronomy

The IceCube Collaboration presents results from a search for sources of high-energy neutrons using four years of data from IceTop, the surface detector array. Researchers have not found any evidence for astrophysical neutrons, but the results have allowed the collaboration to set new limits that constrain the possible galactic neutron sources. These results have just been submitted to the Astrophysical Journal. […]

Read More »


Rethinking PINGU, a world-class instrument for neutrino oscillation studies

The Precision IceCube Next Generation Upgrade (PINGU) is the proposed infill extension in a region at the center of the IceCube Neutrino Observatory that will lower the energy threshold to a few GeV, dramatically increasing both the number of GeV-scale neutrinos detected by IceCube and, more importantly, the precision with which they are measured. […]

Read More »


Searching for dark matter using IceCube cascades

The IceCube Collaboration presents a new search for dark matter annihilation from the galactic center and halo using cascade events, i.e., particle showers created by the interaction of electron and tau neutrinos and Z-boson mediated muon neutrinos. Scientists searched for interactions starting in the DeepCore subarray between May 2011 and May 2012 and found no neutrino excess with respect to the background-only hypothesis, which allowed them to derive upper limits on dark matter candidates with masses between 30 GeV and 10 TeV. These results have been submitted today to the European Physical Journal C. […]

Read More »



A first search for sterile neutrinos in IceCube

The IceCube Collaboration has performed two independent searches for light sterile neutrinos, both with one year of data, searching for sterile neutrinos in the energy range between approximately 320 GeV and 20 TeV. IceCube has not found any anomalous disappearance of muon neutrinos and has placed new exclusion limits on the parameter space of the 3+1 model, a scenario with only one sterile neutrino. These results have been submitted today to Physical Review Letters. […]

Read More »


Improving searches for point sources below 100 TeV

Today, the IceCube Collaboration presents a new technique to lower the energy threshold for neutrino detection while keeping a pointing resolution to within less than a degree. IceCube researchers have used this technique in a joint search with data from a previous analysis using throughgoing muon neutrinos. No point source has been found, but sensitivity for searches below 100 TeV has been improved by a factor of ten. […]

Read More »