First antineutrino energy spectrum from ${}^{235}$U fissions with the STEREO detector at ILL

Abstract

This article reports the measurement of the ${}^{235}$U-induced antineutrino spectrum shape by the STEREO experiment. 43'000 antineutrinos have been detected at about 10 m from the highly enriched core of the ILL reactor during 118 full days equivalent at nominal power. The measured inverse beta decay spectrum is unfolded to provide a pure ${}^{235}$U spectrum in antineutrino energy. A careful study of the unfolding procedure, including a cross-validation by an independent framework, has shown that no major biases are introduced by the method. A significant local distortion is found with respect to predictions around $E_{\nu }\simeq 5.3$ MeV. A gaussian fit of this local excess leads to an amplitude of $A=12.1\pm 3.4\%$ (3.5$\sigma$).

This is the Accepted Manuscript version of an article accepted for publication in J. Phys. G: Nucl. Part. Phys.. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-6471/abd37a. 34 pages, 14 figures

References in corpus (6)

• The Reactor Antineutrino Anomaly
• Sterile neutrino search at NEOS Experiment
• Updated Summation Model: An Improved Agreement with the Daya Bay Antineutrino Fluxes
• Improved Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay
• Reactor antineutrino shoulder explained by energy scale nonlinearities?
• Production and Properties of the Liquid Scintillators used in the Stereo Reactor Neutrino Experiment

Cited by in corpus (16)

• Stereo neutrino spectrum of 235U fission rejects sterile neutrino hypothesis
• Antineutrino Energy Spectrum Unfolding Based on the Daya Bay Measurement and Its Applications
• First measurement of high-energy reactor antineutrinos at Daya Bay
• Measurement of Reactor Antineutrino Flux and Spectrum at RENO
• Joint Measurement of the ${}^{235}$U Antineutrino Spectrum by Prospect and Stereo
• Reactor antineutrino flux and anomaly
• PROSPECT-II Physics Opportunities
• Future searches for light sterile neutrinos at nuclear reactors
• Long term remote reactor power and fuel composition monitoring using antineutrinos
• Status of Anomalies and Sterile Neutrino Searches at Nuclear Reactors
• Prospects of detecting the reactor $\overline{{\nu }_e}$-Ar coherent elastic scattering with a low threshold dual-phase argon time projection chamber at Taishan
• Improved FIFRELIN de-excitation model for neutrino applications
• Towards a Sub-percent Precision Measurement of ${\sin }^2{\theta }_{13}$ with Reactor Antineutrinos
• Exploring Current Constraints on Antineutrino Production by ${}^{241}$Pu and Paths Towards the Precision Reactor Flux Era
• Status and Perspectives of Neutrino Physics
• Matter Effects of Sterile Neutrino in Light of Renormalization-Group Equations