ISGTW has a story about the search for neutrinos at the Japan Proton Accelerator Research Complex, with some detail on the various types of neutrinos and the problems in finding them. In particular, the Japanese attempt to find the ‘theta13’ neutrino via the T2K experiment.
The likelihood that a scientist will see a particular type of neutrino changes periodically over time, oscillating like the rise and fall of a merry-go-round. Three different constant angles determine the rate at which those probabilities oscillate. Scientists have already seen muon and tau neutrino oscillation, and measured two of the three angles. The third angle, theta13, is much tricker to measure, however, because it is very small. And that’s where the Tokai-to-Kamioka (T2K) experiment in Japan comes into the picture.
The image above is the first T2K event seen in Super-Kamiokande (the name of the Japanese Accelerator), where each dot is a photo multiplier tube that detected light.
via Feature – A neutrino’s journey: From accelerator to analysis.
@ John E Royer
Neutrinos are weakly interacting and thus aren’t absorbed nearly often enough to account for these losses.
An Alternative Explanation
It is claimed the reason slightly fewer neutrinos are detected after traveling through the earth is because they oscillate. Why would traveling through the earth cause them to oscillate and thus become undetectable? Now you can say they oscillate based on distance from the source, but what does that have to do with traveling throught the earth?
Wouldn’t a much simplier explanation be that some of these neutrinos are absorbed traveling through the earth? Also, what about the missing neutrinos from the sun?
If neutrinos were viewed as a type of neutral radiation and some of this neutral radiation is absorbed before it even leaves the sun and a little bit more is absorbed traveling through the earth, the missing neutrino problem is solved.