Fuel-Composition Dependent Reactor Antineutrino Yield at RENO
| Autor: | S. B. Kim, J. Y. Kim, J. G. Kim, Seyong Kim, D. E. Jung, J. H. Choi, J. S. Jang, Doh-Kwon Lee, Hyonsan Seo, K. K. Joo, M. Y. Pac, I. T. Lim, W. Kim, Dong Ho Moon, S. h. Seo, Hang Lee, K. Ju, C. D. Shin, Jung-Hyun Kim, E. Kwon, J. Y. Yang, J. W. Seo, G. Bak, Carsten Rott, Y. C. Lee, S. H. Jeon, J. Yoo, Y. S. Park, Intae Yu, H. I. Jang |
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| Rok vydání: | 2019 |
| Předmět: |
Physics
Semileptonic decay Isotope Fission Analytical chemistry FOS: Physical sciences General Physics and Astronomy Composition (combinatorics) 01 natural sciences High Energy Physics - Experiment High Energy Physics - Experiment (hep-ex) Inverse beta decay Yield (chemistry) 0103 physical sciences 010306 general physics Electron neutrino |
| Zdroj: | Physical Review Letters |
| ISSN: | 1079-7114 |
| Popis: | We report a fuel-dependent reactor electron antineutrino ($\overline{\nu}_e$) yield using six 2.8 GW$_{\text{th}}$ reactors in the Hanbit nuclear power plant complex, Yonggwang, Korea. The analysis uses $850\,666$ $\overline{\nu}_e$ candidate events with a background fraction of 2.0 % acquired through inverse beta decay (IBD) interactions in the near detector for 1807.9 live days from August 2011 to February 2018. Based on multiple fuel cycles, we observe a fuel $^{235}$U dependent variation of measured IBD yields with a slope of $(1.51 \pm 0.23) \times 10^{-43} $cm$^2$/fission and measure a total average IBD yield of $(5.84 \pm 0.13) \times 10^{-43} $cm$^2$/fission. The hypothesis of no fuel-dependent IBD yield is ruled out at 6.6 $\sigma$. The observed IBD yield variation over $^{235}$U isotope fraction does not show significant deviation from the Huber-Mueller (HM) prediction at 1.3 $\sigma$. The measured fuel-dependent variation determines IBD yields of $(6.15 \pm 0.19) \times 10^{-43} $cm$^2$/fission and $(4.18\pm 0.26) \times 10^{-43} $cm$^2$/fission for two dominant fuel isotopes $^{235}$U and $^{239}$Pu, respectively. The measured IBD yield per $^{235}$U fission shows the largest deficit relative to the HM prediction. Reevaluation of the $^{235}$U IBD yield per fission may mostly solve the Reactor Antineutrino Anomaly (RAA) while $^{239}$Pu is not completely ruled out as a possible contributor of the anomaly. We also report a 2.9 $\sigma$ correlation between the fractional change of the 5 MeV excess and the reactor fuel isotope fraction of $^{235}$U. Comment: 6 pages and 5 figures, v4 note: (1) data files for figure 1, figure 2, figure 5 are included for arXiv users (2) minor modifications in abstract and main text for clarification |
| Databáze: | OpenAIRE |
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