1. Extraction of the $^{235}$U and $^{239}$Pu Antineutrino Spectra at Daya Bay
- Author
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Daya Bay Collaboration, Adey, D., An, F. P., Balantekin, A. B., Band, H. R., Bishai, M., Blyth, S., Cao, D., Cao, G. F., Cao, J., Chang, J. F., Chang, Y., Chen, H. S., Chen, S. M., Chen, Y., Chen, Y. X., Cheng, J., Cheng, Z. K., Cherwinka, J. J., Chu, M. C., Chukanov, A., Cummings, J. P., Dash, N., Deng, F. S., Ding, Y. Y., Diwan, M. V., Dohnal, T., Dove, J., Dvorak, M., Dwyer, D. A., Gonchar, M., Gong, G. H., Gong, H., Gu, W. Q., Guo, J. Y., Guo, L., Guo, X. H., Guo, Y. H., Guo, Z., Hackenburg, R. W., Hans, S., He, M., Heeger, K. M., Heng, Y. K., Higuera, A., Hor, Y. K., Hsiung, Y. B., Hu, B. Z., Hu, J. R., Hu, T., Hu, Z. J., Huang, H. X., Huang, X. T., Huang, Y. B., Huber, P., Jaffe, D. E., Jen, K. L., Ji, X. L., Ji, X. P., Johnson, R. A., Jones, D., Kang, L., Kettell, S. H., Koerner, L. W., Kohn, S., Kramer, M., Langford, T. J., Lee, J., Lee, J. H. C., Lei, R. T., Leitner, R., Leung, J. K. C., Li, C., Li, F., Li, H. L., Li, Q. J., Li, S., Li, S. C., Li, S. J., Li, W. D., Li, X. N., Li, X. Q., Li, Y. F., Li, Z. B., Liang, H., Lin, C. J., Lin, G. L., Lin, S., Lin, S. K., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, J. C., Liu, J. L., Liu, Y., Liu, Y. H., Lu, C., Lu, H. Q., Lu, J. S., Luk, K. B., Ma, X. B., Ma, X. Y., Ma, Y. Q., Marshall, C., Caicedo, D. A. Martinez, McDonald, K. T., McKeown, R. D., Mitchell, I., Lepin, L. Mora, Napolitano, J., Naumov, D., Naumova, E., Ochoa-Ricoux, J. P., Olshevskiy, A., Pan, H. -R., Park, J., Patton, S., Pec, V., Peng, J. C., Pinsky, L., Pun, C. S. J., Qi, F. Z., Qi, M., Qian, X., Raper, N., Ren, J., Rosero, R., Roskovec, B., Ruan, X. C., Steiner, H., Sun, J. L., Treskov, K., Tse, W. -H., Tull, C. E., Viren, B., Vorobel, V., Wang, C. H., Wang, J., Wang, M., Wang, N. Y., Wang, R. G., Wang, W., Wang, X., Wang, Y., Wang, Y. F., Wang, Z., Wang, Z. M., Wei, H. Y., Wei, L. H., Wen, L. J., Whisnant, K., White, C. G., Wong, H. L. H., Wong, S. C. F., Worcester, E., Wu, Q., Wu, W. J., Xia, D. M., Xing, Z. Z., Xu, J. L., Xue, T., Yang, C. G., Yang, L., Yang, M. S., Yang, Y. Z., Ye, M., Yeh, M., Young, B. L., Yu, H. Z., Yu, Z. Y., Yue, B. B., Zeng, S., Zhan, L., Zhang, C., Zhang, C. C., Zhang, F. Y., Zhang, H. H., Zhang, J. W., Zhang, Q. M., Zhang, R., Zhang, X. F., Zhang, X. T., Zhang, Y. M., Zhang, Y. X., Zhang, Y. Y., Zhang, Z. J., Zhang, Z. P., Zhang, Z. Y., Zhao, J., Zhou, L., Zhuang, H. L., and Zou, J. H.
- Subjects
High Energy Physics - Experiment (hep-ex) ,Physics - Instrumentation and Detectors ,FOS: Physical sciences ,Instrumentation and Detectors (physics.ins-det) ,Nuclear Experiment ,High Energy Physics - Experiment - Abstract
This Letter reports the first extraction of individual antineutrino spectra from $^{235}$U and $^{239}$Pu fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses $3.5\times 10^6$ inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, $^{235}$U and $^{239}$Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4--6~MeV, a 7\% (9\%) excess of events is observed for the $^{235}$U ($^{239}$Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is $4.0\sigma$ for $^{235}$U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at $5.3\sigma$. In the energy range of 4--6~MeV, a maximal local discrepancy of $6.3\sigma$ is observed., Comment: Updated title
- Published
- 2019