Speaker
Description
The Jiangmen Underground Neutrino Observatory (JUNO) is a 20-kiloton liquid scintillator detector located approximately 650 m underground in southern China. JUNO’s primary goals are to determine the neutrino mass ordering and precisely measure the neutrino oscillation parameters $\Delta m^2_{31}$, $\Delta m^2_{21}$, and $\rm{sin}^2\theta_{12}$. The measurement relies on reactor antineutrinos emitted from two nuclear power plants at an average baseline of about 53 km, corresponding to the first solar oscillation maximum, and detected via the inverse beta decay reaction. The first physics data taking started from 26 August 2025 with an exposure of 59.1 days and has achieved world-leading precision on the solar oscillation parameters. The reference reactor antineutrino spectrum directly affects the precision of parameter extraction. For the first oscillation analysis, the Daya Bay spectrum measurement is used to constrain the antineutrino spectrum. The Taishan Antineutrino Observatory (TAO), a satellite detector of JUNO, has recently started physics data taking and is expected to provide high-precision measurements of the reactor antineutrino spectrum.
This poster presents a semi-model-independent approach that combines Daya Bay near-detector data with theoretical models to constrain the reactor antineutrino spectrum for JUNO’s first oscillation analysis. The incorporation of TAO data into this combination will also be discussed.