The standard model of particle physics has been very successful in describing the Strong, Weak and Electromagnetic interactions of fundamental particles over a wide range of energies. However, recent experimental evidence of lepton flavor violation has been shown in the oscillation of massive neutrinos. These observations are a strong indication that the standard model treatment for the weak interactions of fundamental particles is incomplete. We can incorporate these new observations into our existing framework by generalizing the standard model: allowing neutrinos to acquire mass.

The Daya Bay experiment plans to determine the last undetermined mixing angle in the leptonic mixing matrix, &thetas;₁₃, by studying the anomalous disappearance of reactor antineutrinos at baselines up to 2 km. The sensitivity of the Daya Bay experiment to low energy reactor neutrinos is possible because of a newly developed Gadolinium loaded liquid scintillator (GdLS), which acts as both a target and detection medium for neutrino induced inverse beta decays. The research and development informing the experimental design are discussed, with particular emphasis on the measured optical properties of GdLS. These results are necessary for understanding the signal and background event reconstruction when the experiment comes online in 2012. The projected sensitivity to &thetas;₁₃ and the status of detector construction as of March 2010 are discussed.