Is There Really A Fourth Neutrino Out There In The Universe?
“Regardless of what the ultimate explanation is, it’s quite clear that the normal Standard Model, with three neutrinos that oscillate between electron/muon/tau types, cannot account for everything we’ve observed up to this point. The LSND results, once dismissed as a baffling experimental result that must surely be wrong, have been confirmed in a big way. With reactor deficiencies, MiniBooNe’s results, and three new experiments on the horizon to gather more data about these mysteriously misbehaving particles, we may be poised for a new revolution in physics.
The high-energy frontier is only one way we have of learning about the Universe on a fundamental level. Sometimes, we just have to know what the right question to ask truly is. By looking at the lowest-energy particles at different distances from where they’re generated, we just might take the next great leap in our knowledge of physics. Welcome to the era of the neutrino, which is taking us, at last, beyond the Standard Model.”
No matter how good, compelling, elegant, or successful our theories about the Universe are, they must always be confronted with experiments. If there’s a new, conflicting experimental result, it must be verified and validated independently to make sure it’s correct. Well, that was what the LSND experiment was for neutrinos and the Standard Model: an outlier that couldn’t be explained consistently with the other observations. After 16 years, the MiniBooNe experiment has released their final results: validating LSND and presenting a combined 6.0-sigma significance. Neutrinos don’t behave as they should.