A step forward in understanding the universe: The latest results from the Daya Bay experiment

Schematic picture for Daya Bay reactor antineutrino experiment

Why is the current universe dominated by matter when there should have been equal amounts of matter and anti-matter at the beginning? One of the keys to answering this question is to find out a currently undiscovered charge-parity (CP) violation in the lepton sector. The CP violation can be tested through studies of the phenomenon called neutrino oscillation. Neutrino oscillation occurs because the weak eigenstates, |νl>(l=e,μ,τ), and mass eigenstates, |νi>(i=1,2,3), are mixed, as follows:where UPMNS is the 3 × 3 Pontecorvo-Maki-Nakagawa-Sakata mixing matrix, which is defined with three mixing angles, θ12, θ23, and θ13, and one complex Dirac CP phase, δCP.