Future Searches for Light Sterile Neutrinos at Nuclear Reactors.

We study the optimization of a green-field, two-baseline reactor experiment with respect to the sensitivity for electron antineutrino disappearance in search of a light sterile neutrino. We consider both commercial and research reactors and identify as key factors the distance of closest approach and detector energy resolution. We find that a total of 5 tons of detectors deployed at a commercial reactor with a closest approach of 25 m can probe the mixing angle $\sin^22\theta$ down to $\sim5\times10^{-3}$ around $\Delta m^2\sim 1$ eV$^2$. The same detector mass deployed at a research reactor can be sensitive up to $\Delta m^2\sim20-30$ eV$^2$ assuming a closest approach of 3 m and excellent energy resolution, such as that projected for the Taishan Antineutrino Observatory (TAO). We also find that lithium doping of the reactor could be effective in increasing the sensitivity for higher $\Delta m^2$ values.