1. Improved Measurement of the Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay
- Author
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An, FP, Bai, WD, Balantekin, AB, Bishai, M, Blyth, S, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, HY, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, Y-C, Cheng, ZK, Cherwinka, JJ, Chu, MC, Cummings, JP, Dalager, O, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dolzhikov, D, Dove, J, Dugas, KV, Duyang, HY, Dwyer, DA, Gallo, JP, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Han, Y, Hans, S, He, M, Heeger, KM, Heng, YK, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, JH, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, HL, Li, JJ, Li, QJ, Li, RH, Li, S, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Liu, JX, Lu, C, Lu, HQ, and Luk, KB
- Subjects
Nuclear and Plasma Physics ,Particle and High Energy Physics ,Physical Sciences ,Nuclear Reactors ,Uranium ,Daya Bay Collaboration ,Mathematical Sciences ,Engineering ,General Physics ,Mathematical sciences ,Physical sciences - Abstract
Reactor neutrino experiments play a crucial role in advancing our knowledge of neutrinos. In this Letter, the evolution of the flux and spectrum as a function of the reactor isotopic content is reported in terms of the inverse-beta-decay yield at Daya Bay with 1958 days of data and improved systematic uncertainties. These measurements are compared with two signature model predictions: the Huber-Mueller model based on the conversion method and the SM2018 model based on the summation method. The measured average flux and spectrum, as well as the flux evolution with the ^{239}Pu isotopic fraction, are inconsistent with the predictions of the Huber-Mueller model. In contrast, the SM2018 model is shown to agree with the average flux and its evolution but fails to describe the energy spectrum. Altering the predicted inverse-beta-decay spectrum from ^{239}Pu fission does not improve the agreement with the measurement for either model. The models can be brought into better agreement with the measurements if either the predicted spectrum due to ^{235}U fission is changed or the predicted ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu spectra are changed in equal measure.
- Published
- 2023