Reactor Neutrino Experiments Compared to Superbeams

We present a detailed quantitative discussion of the measurement of the leptonic mixing angle $\sin^2 2 \theta_{13}$ with a future reactor neutrino oscillation experiment consisting of a near and far detector. We perform a thorough analysis of the impact of various systematical errors and compare the resulting physics potential to the one of planned first-generation superbeam experiments. Furthermore, we investigate the complementarity of both types of experiments. We find that, under realistic assumptions, a determination of $\sin^2 2 \theta_{13}$ down to $10^{-2}$ is possible with reactor experiments. They are thus highly competitive to first-generation superbeams and may be able to test $\sin^2 2 \theta_{13}$ on shorter timescales. In addition, we find that the combination of a KamLAND-size reactor experiment with one or two superbeams could substantially improve the ability to access the neutrino mass hierarchy or the leptonic CP phase.