Improved Measurement of the Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Abstract

Reactor neutrino experiments play a crucial role in advancing our knowledge of neutrinos. A precise measurement of reactor electron antineutrino flux and spectrum evolution can be key inputs in improving the knowledge of neutrino mass and mixing as well as reactor nuclear physics and searching for physics beyond the standard model. In this work, the evolution of the flux and spectrum as a function of the reactor isotopic content is reported in terms of the inverse-beta-decay yield at Daya Bay with 1958 days of data and improved systematic uncertainties. These measurements are compared with two signature model predictions: the Huber-Mueller model based on the conversion method and the SM2018 model based on the summation method. The measured average flux and spectrum, as well as their evolution with the 239Pu fraction, are inconsistent with the predictions of the Huber-Mueller model. In contrast, the SM2018 model is shown to agree with the average flux and its evolution but fails to describe the energy spectrum. Altering the predicted IBD spectrum from 239Pu does not improve the agreement with the measurement for either model. The models can be brought into better agreement with the measurements if either the predicted spectrum due to 235U is changed or the predicted 235U, 238U, 239Pu, and 241Pu spectra are changed in equal measure.

References in corpus (13)

• Observation of electron-antineutrino disappearance at Daya Bay
• The Reactor Antineutrino Anomaly
• Measurement of the solar neutrino capture rate with gallium metal. III: Results for the 2002--2007 data-taking period
• Sterile neutrino search at NEOS Experiment
• Improved measurements of the neutrino mixing angle ${\theta }_{13}$ with the Double Chooz detector
• Results from the Baksan Experiment on Sterile Transitions (BEST)
• Updated Summation Model: An Improved Agreement with the Daya Bay Antineutrino Fluxes
• Improved Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay
• Search for a Light Sterile Neutrino at Daya Bay
• Reevaluating reactor antineutrino spectra with new measurements of the ratio between ${}^{235}$U and ${}^{239}$Pu $\beta$ spectra
• Stereo neutrino spectrum of 235U fission rejects sterile neutrino hypothesis
• The 5 MeV bump - a nuclear whodunit mystery
• Measurement of Reactor Antineutrino Flux and Spectrum at RENO

Cited by in corpus (5)

• Impacts of dark energy on weighing neutrinos after DESI BAO
• Reactor antineutrino flux and anomaly
• Comprehensive Measurement of the Reactor Antineutrino Spectrum and Flux at Daya Bay
• Long term remote reactor power and fuel composition monitoring using antineutrinos
• Analysis of reactor burnup simulation uncertainties for antineutrino spectrum prediction