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arXiv · 2107.03371

Joint Measurement of the $^{235}$U Antineutrino Spectrum by Prospect and Stereo

Abstract

The PROSPECT and STEREO collaborations present a combined measurement of the pure $^{235}$U antineutrino spectrum, without site specific corrections or detector-dependent effects. The spectral measurements of the two highest precision experiments at research reactors are found to be compatible with $\chi^2/\mathrm{ndf} = 24.1/21$, allowing a joint unfolding of the prompt energy measurements into antineutrino energy. This $\bar{\nu}_e$ energy spectrum is provided to the community, and an excess of events relative to the Huber model is found in the 5-6 MeV region. When a Gaussian bump is fitted to the excess, the data-model $\chi^2$ value is improved, corresponding to a $2.4\sigma$ significance.

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H. Almazán, M. Andriamirado, A. B. Balantekin, H. R. Band, C. D. Bass, D. E. Bergeron, L. Bernard, A. Blanchet, A. Bonhomme, N. S. Bowden, C. D. Bryan, C. Buck, T. Classen, A. J. Conant, G. Deichert, P. del Amo Sanchez, A. Delgado, M. V. Diwan, M. J. Dolinski, I. El Atmani, A. Erickson, B. T. Foust, J. K. Gaison, A. Galindo-Uribarri, C. E. Gilbert, S. Hans, A. B. Hansell, K. M. Heeger, B. Heffron, D. E. Jaffe, S. Jayakumar, X. Ji, D. C. Jones, J. Koblanski, O. Kyzylova, L. Labit, J. Lamblin, C. E. Lane, T. J. Langford, J. LaRosa, A. Letourneau, D. Lhuillier, M. Licciardi, M. Lindner, B. R. Littlejohn, X. Lu, J. Maricic, T. Materna, M. P. Mendenhall, A. M. Meyer, R. Milincic, P. E. Mueller, H. P. Mumm, J. Napolitano, R. Neilson, J. A. Nikkel, S. Nour, J. L. Palomino, H. Pessard, D. A. Pushin, X. Qian, J. -S. Réal, J. -S. Ricol, C. Roca, R. Rogly, R. Rosero, T. Salagnac, V. Savu, S. Schoppmann, M. Searles, V. Sergeyeva, T. Soldner, A. Stutz, P. T. Surukuchi, M. A. Tyra, R. L. Varner, D. Venegas-Vargas, M. Vialat, P. B. Weatherly, C. White, J. Wilhelmi, A. Woolverton, M. Yeh, C. Zhang, X. Zhang. 2021-07-07. Joint Measurement of the $^{235}$U Antineutrino Spectrum by Prospect and Stereo. https://doi.org/10.1103/physrevlett.128.081802

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