K2K experiment
The K2K experiment (KEK to Kamioka) was a neutrino experiment that ran from June 1999 to November 2004. It used muon neutrinos from a well-controlled and well-understood beam to verify the oscillations previously observed by Super-Kamiokande using atmospheric neutrinos. This was the first positive measurement of neutrino oscillations in which both the source and detector were fully under experimenters' control. Previous experiments relied on neutrinos from the Sun or from cosmic sources. The experiment found oscillation parameters which were consistent with those measured by Super-Kamiokande.
K2K is a neutrino experiment which directed a beam of muon neutrinos (
ν
μ) from the 12 GeV proton synchrotron at the KEK, located in Tsukuba, Ibaraki, to the Kamioka Observatory, located in Kamioka, Gifu, about 250 km away. The muon neutrinos travelled through Earth, which allowed them to oscillate (change) into other flavours of neutrinos, namely into electron neutrinos (
ν
e) and tau neutrinos (
ν
τ). K2K however, focused only on
ν
μ →
ν
τ oscillations.
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