Heidelberg 1999 – scientific programme

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PV: Plenarvorträge

PV V

PV V: Plenary Talk

Wednesday, March 17, 1999, 08:15–09:00, CH 1

Evidence for Neutrino Oscillations — •Yoji Totsuka — Kamioka Oberservatory, Institute for Cosmic Ray Research, University of Tokio, Kamioka, Japan

Recently Super-Kmiokande published the results that show clear evidence for neutrino oscillations in atmospheric neutrinos. Neutrinoi oscillations occur only when neutrinos have finite mass and non-conservation of lepton flavor number (muon number electron number, etc.) It has important implications in particle physics and cosmology, hence raising a lot of interests in the community. The anomaly in atmospheric neutrinos, a deficit of muon neutrinos, has been known since 1988, but due to low statistics of the observed number of events, the anomaly was considered to be controversial. The Super-Kamiokande experiment now has events five times more than those combined of all the previous emperiments. Two other experiments also published the results that support the Super-Kamiokande results, though statistically less significant, further strengthening evidence for neutrino oscillations.
In this lecture I would, after a brief introduction, describe the current status on atmospheric-neutrino studies and show the results that indicate evidence for neutrino oscillations. I would also like to discuss what future experiments should do for a further scrutiny into neutrino mass.