The American Physical Society meeting on astronomy, astrophysics, cosmology and particle physics, the so-called April meeting, closes today in Washington DC. The IceCube Collaboration has presented brand new results on neutrino oscillations that are comparable in precision to long-baseline neutrino experiments. From WIPAC, many PhD students and more senior staff presented results about IceCube, including the masterclass, along with results on CTA and Fermi.
Those of us working with high-energy neutrinos always have great expectations for a new year, since the highest energy neutrino ever could show up or a joint detection of a neutrino and another cosmic messenger might point us to the much sought-after sources.
In an effort to fill in the blanks of the Standard Model of particle physics, science has been conducting a diligent search for a hypothesized particle known as the “sterile neutrino.” Now, with the latest results from an icy particle detector at the South Pole, scientists are almost certain that there is no such particle.
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.
IceCube data are stubbornly showing us only a glimpse of the extreme universe at a time. Ever since the discovery of a flux of TeV-PeV astrophysical neutrinos, scientists have been studying various potential sources of these neutrinos, and little by little, learning details about the composition of the cosmic neutrino flux.