\theta_{13} was the last of the neutrino mixing angles to be measured. The Daya Bay experiment was designed to measure it, and has the most precise value for it

\theta_{13} was the last of the neutrino mixing angles to be measured. The Daya Bay experiment was designed to measure it, and has the most precise value for it. It's hard to do, and the purpose for which Daya Bay was built. http://en.wikipedia.org/wiki/Neutrino_oscillation http://en.wikipedia.org/wiki/Neutrino_oscillation I'm in a nearby field, and work with a bunch of folks in the thick of it. From a quick read, the new news is that Daya Bay has roughly doubled their precision for \theta_{13} to ~10 sigma from ~5. The next big thing in the field is a hunt for what people call \delta, a parameter that should encapsulate any CP violation in the neutrino sector.