(sub)eV Sterile Neutrinos: experimental aspects

The majority of neutrino oscillation results are explained by the three-neutrino formalism. But a bunch of anomalies in short baseline oscillation data can be interpreted by invoking a fourth neutrino. This new state would be separated from the three standard neutrinos by a squared mass difference and would have mixing angles of sin2⁡2θee≳0.01 and sin2⁡2θμe≳0.001, in the electron disapperance and appearance channels, respectively. This new – sterile – neutrino would not feel standard model interactions but mix with the others, with a L/E ratio of about 1 m/MeV. Such a scenario calling for new physics beyond the standard model needs to be tested with new data.