Precision Results on $\theta_{13}$ from Daya Bay

The Daya Bay Reactor Neutrino Experiment measures the neutrino mixing angle $\theta_{13}$ with high sensitivity, using functionally identical detectors at appropriate distances from the cores of a nuclear power plant. We have analyzed 217 days of data with six detectors, and 404 days with the full complement of eight detectors, obtaining a sample of over two million $\bar\nu_ep\to e^+n$ events. Combining rate and spectral shape information, we find $\sin^22\theta_{13}=0.084\pm0.005$ and $\Delta m^2_{ee}=\left(2.44^{+0.10}_{-0.11}\right)\times10^{-3}$~eV$^2$ for events where the neutron captures on gadolinium. Also, using the six detector data set and a rate analysis based on $np$ capture, we find $\sin^22\theta_{13}=0.083\pm0.018$. We will present details of these results, including a discussion of backgrounds and systematic uncertainties.