First measurement of high-energy reactor antineutrinos at Daya Bay

Abstract

This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12~MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10~MeV is rejected with a significance of 6.2 standard deviations. A 29\% antineutrino flux deficit in the prompt energy region of 8-11~MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-$Q_{\beta }$ isotopes in commercial reactors.

arXiv comment7 pages, 4 figures, accepted by Physical Review Letters

References in corpus (36)

• The Reactor Antineutrino Anomaly
• Improved Predictions of Reactor Antineutrino Spectra
• On the determination of anti-neutrino spectra from nuclear reactors
• The angular distribution of the reaction ${\bar{\nu }}_e+p\to e^{+}+n$
• GADZOOKS! Antineutrino Spectroscopy with Large Water Cerenkov Detectors
• Observation of Energy and Baseline Dependent Reactor Antineutrino Disappearance in the RENO Experiment
• Measurement of electron antineutrino oscillation with 1958 days of operation at Daya Bay
• Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay
• Systematic Uncertainties in the Analysis of the Reactor Neutrino Anomaly
• Measurement of electron antineutrino oscillation based on 1230 days of operation of the Daya Bay experiment
• Improved measurements of the neutrino mixing angle ${\theta }_{13}$ with the Double Chooz detector
• Production of Radioactive Isotopes through Cosmic Muon Spallation in KamLAND
• New antineutrino energy spectra predictions from the summation of beta decay branches of the fission products
• Spectral Structure of Electron Antineutrinos from Nuclear Reactors
• Updated Summation Model: An Improved Agreement with the Daya Bay Antineutrino Fluxes
• Improved Short-Baseline Neutrino Oscillation Search and Energy Spectrum Measurement with the PROSPECT Experiment at HFIR
• Improved Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay
• Experimental Determination of the Antineutrino Spectrum of the Fission Products of ${}^{238}$U
• The Detector System of The Daya Bay Reactor Neutrino Experiment
• Reactor antineutrino anomaly in light of recent flux model refinements
• First-forbidden transitions in the reactor anomaly
• First-forbidden transitions in the reactor anomaly
• Total Absorption Spectroscopy Study of ${}^{92}$Rb Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape
• Reevaluating reactor antineutrino spectra with new measurements of the ratio between ${}^{235}$U and ${}^{239}$Pu $\beta$ spectra
• Extraction of the ${}^{235}$U and ${}^{239}$Pu Antineutrino Spectra at Daya Bay
• Total Absorption Gamma-Ray Spectroscopy of 87Br, 88Br and 94Rb Beta-Delayed Neutron Emitters
• Beta-decay studies for applied and basic nuclear physics
• Measurement of the Antineutrino Spectrum from ${}^{235}$U Fission at HFIR with PROSPECT
• Improved Measurement of the Reactor Antineutrino Flux at Daya Bay
• Total Absorption Spectroscopy Study of the Beta Decay of ${}^{86}$Br and ${}^{91}$Rb
• Antineutrino Energy Spectrum Unfolding Based on the Daya Bay Measurement and Its Applications
• Reevaluating Reactor Antineutrino Anomalies with Updated Flux Predictions
• First antineutrino energy spectrum from ${}^{235}$U fissions with the STEREO detector at ILL
• Accurate Measurement of the Electron Antineutrino Yield of U-235 Fissions from the STEREO Experiment with 119 Days of Reactor-On Data
• Joint Measurement of the ${}^{235}$U Antineutrino Spectrum by Prospect and Stereo
• Measuring cosmogenic Li9 background in a reactor neutrino experiment

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