A1 Journal article (refereed)
First-forbidden transitions in the reactor anomaly (2019)
Hayen, L., Kostensalo, J., Severijns, N., & Suhonen, J. (2019). First-forbidden transitions in the reactor anomaly. Physical Review C, 100(5), Article 054323. https://doi.org/10.1103/PhysRevC.100.054323
JYU authors or editors
Publication details
All authors or editors: Hayen, L.; Kostensalo, J.; Severijns, N.; Suhonen, J.
Journal or series: Physical Review C
ISSN: 2469-9985
eISSN: 2469-9993
Publication year: 2019
Volume: 100
Issue number: 5
Article number: 054323
Publisher: American Physical Society
Publication country: United States
Publication language: English
DOI: https://doi.org/10.1103/PhysRevC.100.054323
Publication open access: Not open
Publication channel open access:
Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/66520
Publication is parallel published: https://arxiv.org/abs/1805.12259
Abstract
We describe here microscopic calculations performed on the dominant forbidden transitions in reactor antineutrino spectra above 4 MeV using the nuclear shell model. By taking into account Coulomb corrections in the most complete way, we calculate the shape factor with the highest fidelity and show strong deviations from allowed approximations and previously published results. Despite small differences in the ab initio electron cumulative spectra, large differences on the order of several percent are found in the antineutrino spectra. Based on the behavior of the numerically calculated shape factors we propose a parametrization of forbidden spectra. Using Monte Carlo techniques we derive an estimated spectral correction and uncertainty due to forbidden transitions. We establish the dominance and importance of forbidden transitions in both the reactor anomaly and spectral shoulder analysis with their respective uncertainties. Based on these results, we conclude that a correct treatment of forbidden transitions is indispensable in both the normalization anomaly and spectral shoulder.
Keywords: nuclear physics; particle physics
Free keywords: beta decay; electroweak interactions in nuclear physics; fission; neutrino interactions; nuclear reactors; shell model
Contributing organizations
Related projects
- Nuclear Theory for Fundamental Physics
- Suhonen, Jouni
- Research Council of Finland
Ministry reporting: Yes
Reporting Year: 2019
JUFO rating: 2