05.08.2015
IceCube: Discovery of a neutrino with new record-energy
Physicists from the IceCube Neutrino Observatory have presented the observation of a neutrino with unprecedented high energy at the 34th International Cosmic Ray Conference in The Hague, Netherland, in August 2015. With 2.6 PeV this newly detected neutrino also breaks the energy record of the neutrino observed in 2013 with 2.2 PeV. The neutrino has caused a tale-shaped signal in the detector, so that the direction from which it came is known with an accuracy better than 1 °. Also physicists from the Excellence Cluster Universe of the TU München are members of the IceCube Collaboration.
The Earth is continuously bombarded by high-energy cosmic rays with extremely high energies up to ten million times higher than energies produced at Earth in man-made particle accelerators like the Large Hadron Collider (LHC). But their astronomical sources in the universe are still unknown. To solve this puzzle, more than 50 years ago physicists proposed to measure cosmic neutrinos as signals from these sources, because neutrinos travel undisturbed on straight paths through the universe. However their detection is challenging and requires extremely large detectors.
After several decades of development, the construction of the IceCube Neutrino Observatory at the geographic South Pole was completed in 2010 by an international collaboration. The detector measures the light that is produced in neutrino interactions within the ice of the observatory. Already in the measurement data of the first years neutrino signals of cosmic origin were discovered. The results were published in Science in 2013.
In the new data covering six years of operation, physicists from the IceCube collaboration now discovered an extremely high energy neutrino with 2,6 PeV that is most likely of cosmic origin. The signal reveals a long track and its direction could be measured with an accuracy better than 1°. This now allows to search for astronomical sources in the direction of this event.