Joint Search for Light Sterile Neutrino Oscillations by PROSPECT, STEREO, and Daya Bay

The PROSPECT, STEREO, and Daya Bay experiments have each delivered important contributions to reactor antineutrino research. PROSPECT and STEREO focus on short-baseline (~10 m) measurements using highly enriched uranium (HEU) research reactors, where nearly all antineutrinos originate from the fissions of U-235. Meanwhile, Daya Bay investigates antineutrino emissions from low-enriched uranium (LEU) commercial reactors, utilizing detectors positioned at longer baselines ranging from 500 to 2000 meters, and accounting for contributions from multiple isotopes. Individually, these experiments have set stringent constraints on sterile neutrino oscillation parameters, each probing different regions of parameter space. A new collaborative effort now combines the complete datasets from all three experiments to enable a more comprehensive and precise investigation of light sterile neutrinos. By combining HEU and LEU data, this joint analysis enhances sensitivity to oscillation signatures that exceed the reach of any single experiment and provides tighter constraints on anomalies observed in short-baseline studies, such as the gallium anomaly. This talk will present the latest developments and preliminary results from this combined sterile neutrino oscillation search.