Self-consistent calculation of the reactor antineutrino spectra including forbidden transitions

Understand

With the goal of determining the $\theta_{13}$ neutrino oscillation mixing angle, the measurements of reactor antineutrino fluxes at the Double Chooz, RENO and Daya Bay experimental facilities have uncovered a systematic discrepancy between the number of observed events and theoretical expectations.

• In the \emph{ab initio} approach, the total reactor antineutrino spectrum is a weighted sum of spectra resulting from all $\beta$ branches of all fission products in the reactor core.
• At all three facilities a systematic deviation of the number of observed events from the number of predicted events was noticed, i.e., approximately 6\% of the predicted neutrinos were not observed.
• This discrepancy was named the reactor neutrino anomaly.