Double Chooz scientific goal
The neutrino oscillation discovery has been, ten years ago, a major break through in particle physics. It first demonstrated that neutrinos do have mass. It is also an important step to improve the standard model of particle physics.
This oscillation is described by 3 angles. Two of them have been measured and found large. The third one (θ13) is known to be small. There is only an upper limit, from a first experiment at Chooz. This world limit will be revisited this year by Double Chooz, and very soon improved.
The value of this angle is also important for the study of violation of the fundamental symmetry Charge-Parity (so called CP). If θ13 is zero, the standard model does not provide CP violation. If it is large enough, it will be experimentally studied. Very large project (such as LBNE at DUSEL in US) are waiting for information about it to tune their design.
The accelerator experiment T2K based in Japan will measure another neutrino transition, and bring complementary information about θ13. Other reactor experiments are also in good progress, and will bring results in this very important area (Daya Bay, RENO).