Sterile Neutrino Fits

Understand

After a brief review of the results of solar, atmospheric and long-baseline neutrino oscillation experiments which led to the current three-neutrino mixing paradigm, we discuss indications of neutrino oscillation experiments in favor of short-baseline oscillations which require the existence of one or more sterile neutrinos.

• We show that the simplest possibility of existence of one sterile neutrino is not enough to fit all data of short-baseline neutrino oscillation experiments because of two tensions: a tension between neutrino and antineutrino data and a tension between appearance and disappearance data.
• The tension between neutrino and antineutrino data is eliminated with the addition of a second sterile neutrino which allows CP-violating effects in short-baseline experiments.
• In this case the tension between appearance and disappearance data is reduced, but cannot be eliminated.