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Your search keyword '"Li, Y. F."' showing total 18 results
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18 results on '"Li, Y. F."'

1. Neutron radius determination of 133Cs and its impact on the interpretation of CEvNS-CsI measurement

Author

Huang, Y., Xia, S. Y., Li, Y. F., Tu, X. L., Zhang, J. T., Shao, C. J., Yue, K., Ma, P., Niu, Y. F., Li, Z. P., Kuang, Y., Liu, X. Q., Han, J. F., Egelhof, P., Litvinov, Yu. A., Wang, M., Zhang, Y. H., Zhou, X. H., and Sun, Z. Y.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Proton-$^{133}$Cs elastic scattering at low momentum transfer is performed using an in-ring reaction technique at the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou. Recoil protons from the elastic collisions between the internal H$_2$-gas target and the circulating $^{133}$Cs ions at 199.4 MeV/u are detected by a silicon-strip detector. The matter radius of $^{133}$Cs is deduced by describing the measured differential cross sections using the Glauber model. Employing the adopted proton distribution radius, a point-neutron radius of 4.86(21) fm for $^{133}$Cs is obtained. With the newly determined neutron radius, the weak mixing angle sin$^2 \theta_W$ is independently extracted to be 0.227(28) by fitting the coherent elastic neutrino-nucleus scattering data. Our work limits the sin$^2 \theta_W$ value in a range smaller than the ones proposed by the previous independent approaches, and would play an important role in searching new physics via the high precision CE$\nu$NS-CsI cross section data in the near future.

Published
2024

2. First measurement of the yield of $^8$He isotopes produced in liquid scintillator by cosmic-ray muons at Daya Bay

Author

Daya Bay Collaboration, An, F. P., Bai, W. D., Balantekin, A. B., Bishai, M., Blyth, S., Cao, G. F., Cao, J., Chang, J. F., Chang, Y., Chen, H. S., Chen, H. Y., Chen, S. M., Chen, Y., Chen, Y. X., Chen, Z. Y., Cheng, J., Cheng, Y. C., Cheng, Z. K., Cherwinka, J. J., Chu, M. C., Cummings, J. P., Dalager, O., Deng, F. S., Ding, X. Y., Ding, Y. Y., Diwan, M. V., Dohnal, T., Dolzhikov, D., Dove, J., Dugas, K. V., Duyang, H. Y., Dwyer, D. A., Gallo, J. P., 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., Han, Y., Hans, S., He, M., Heeger, K. M., Heng, Y. K., Hor, Y. K., Hsiung, Y. B., Hu, B. Z., Hu, J. R., Hu, T., Hu, Z. J., Huang, H. X., Huang, J. H., 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., Kohn, S., Kramer, M., Langford, T. J., Lee, J., Lee, J. H. C., Lei, R. T., Leitner, R., Leung, J. K. C., Li, F., Li, H. L., Li, J. J., Li, Q. J., Li, R. H., Li, S., Li, S. C., 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., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, J. C., Liu, J. L., Liu, J. X., Lu, C., Lu, H. Q., Luk, K. B., Ma, B. Z., Ma, X. B., Ma, X. Y., Ma, Y. Q., Mandujano, R. C., Marshall, C., McDonald, K. T., McKeown, R. D., Meng, Y., Napolitano, J., Naumov, D., Naumova, E., Nguyen, T. M. T., Ochoa-Ricoux, J. P., Olshevskiy, A., Park, J., Patton, S., Peng, J. C., Pun, C. S. J., Qi, F. Z., Qi, M., Qian, X., Raper, N., Ren, J., Reveco, C. Morales, Rosero, R., Roskovec, B., Ruan, X. C., Russell, B., Steiner, H., Sun, J. L., Tmej, T., Tse, W. -H., Tull, C. E., Tung, Y. C., Viren, B., Vorobel, V., Wang, C. H., Wang, J., Wang, M., Wang, N. Y., Wang, R. G., Wang, W., Wang, X., Wang, Y. F., Wang, Z., Wang, Z. M., Wei, H. Y., Wei, L. H., Wei, W., Wen, L. J., Whisnant, K., White, C. G., Wong, H. L. H., Worcester, E., Wu, D. R., Wu, Q., Wu, W. J., Xia, D. M., Xie, Z. Q., Xing, Z. Z., Xu, H. K., Xu, J. L., Xu, T., Xue, T., Yang, C. G., Yang, L., Yang, Y. Z., Yao, H. F., Ye, M., Yeh, M., Young, B. L., Yu, H. Z., Yu, Z. Y., Yue, B. B., Zavadskyi, V., Zeng, S., Zeng, Y., Zhan, L., Zhang, C., Zhang, F. Y., Zhang, H. H., Zhang, J. L., Zhang, J. W., Zhang, Q. M., Zhang, S. Q., Zhang, X. T., Zhang, Y. M., Zhang, Y. X., Zhang, Y. Y., Zhang, Z. J., Zhang, Z. P., Zhang, Z. Y., Zhao, J., Zhao, R. Z., Zhou, L., Zhuang, H. L., and Zou, J. H.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

Daya Bay presents the first measurement of cosmogenic $^8$He isotope production in liquid scintillator, using an innovative method for identifying cascade decays of $^8$He and its child isotope, $^8$Li. We also measure the production yield of $^9$Li isotopes using well-established methodology. The results, in units of 10$^{-8}\mu^{-1}$g$^{-1}$cm$^{2}$, are 0.307$\pm$0.042, 0.341$\pm$0.040, and 0.546$\pm$0.076 for $^8$He, and 6.73$\pm$0.73, 6.75$\pm$0.70, and 13.74$\pm$0.82 for $^9$Li at average muon energies of 63.9~GeV, 64.7~GeV, and 143.0~GeV, respectively. The measured production rate of $^8$He isotopes is more than an order of magnitude lower than any other measurement of cosmogenic isotope production. It replaces the results of previous attempts to determine the ratio of $^8$He to $^9$Li production that yielded a wide range of limits from 0 to 30\%. The results provide future liquid-scintillator-based experiments with improved ability to predict cosmogenic backgrounds.

Published
2024

3. Inspection of the detection cross section dependence of the Gallium Anomaly

Author

Giunti, C., Li, Y. F., Ternes, C. A., and Xin, Z.

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment, Nuclear Experiment, Nuclear Theory
Abstract

We discuss in detail the dependence of the Gallium Anomaly on the detection cross section. We provide updated values of the size of the Gallium Anomaly and find that its significance is larger than about $5\sigma$ for all the detection cross section models. We discuss the dependence of the Gallium Anomaly on the assumed value of the half life of ${}^{71}\text{Ge}$, which determines the cross sections of the transitions from the ground state of ${}^{71}\text{Ga}$ to the ground state of ${}^{71}\text{Ge}$. We show that a value of the ${}^{71}\text{Ge}$ half life which is larger than the standard one can reduce or even solve the Gallium Anomaly. Considering the short-baseline neutrino oscillation interpretation of the Gallium Anomaly, we show that a value of the ${}^{71}\text{Ge}$ half life which is larger than the standard one can reduce the tension with the results of other experiments. Since the standard value of the ${}^{71}\text{Ge}$ half life was measured in 1985, we advocate the importance of new measurements with modern technique and apparatus for a better assessment of the Gallium Anomaly., Comment: v3: 11 pages, 4 figures, 3 tables, references added, typo corrected

Published
2022
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4. Impact of the Dresden-II and COHERENT neutrino scattering data on neutrino electromagnetic properties and electroweak physics

Author

Corona, M. Atzori, Cadeddu, M., Cargioli, N., Dordei, F., Giunti, C., Li, Y. F., Ternes, C. A., and Zhang, Y. Y.

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment, Nuclear Experiment, Nuclear Theory
Abstract

Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) represents a powerful tool to investigate key electroweak physics parameters and neutrino properties since its first observation in 2017 by the COHERENT experiment exploiting the spallation neutron source at Oak Ridge National Laboratory. In light of the recent detection of such a process with antineutrinos produced by the Dresden-II reactor scattering off a germanium detector, we revisit the limits so far set on the neutrino magnetic moments, charge radii and millicharges as well as on the weak mixing angle. In order to do so, we also include the contribution of elastic neutrino-electron scattering, whose effect becomes non negligible in some beyond the Standard Model theories. By using different hypotheses for the germanium quenching factor and the reactor antineutrino flux, we provide a measurement of the weak mixing angle at the low-energy scale of the Dresden-II reactor experiment and, thanks to a combined analysis with the latest cesium iodide and argon data set released by the COHERENT Collaboration, we deliver updated limits for the neutrino electromagnetic properties. Interestingly, we are able to set a new best upper limit on the electron neutrino charge radius and significantly improve the other CE$\nu$NS-related limits on the neutrino electric charge and magnetic moment., Comment: Matches the published version. 33 pages, 11 figures

Published
2022
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5. First measurement of high-energy reactor antineutrinos at Daya Bay

Author

Daya Bay collaboration, An, F. P., Balantekin, A. B., Band, H. R., Bishai, M., Blyth, S., 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., Cummings, J. P., Dalager, O., Deng, F. S., Ding, Y. Y., Diwan, M. V., Dohnal, T., Dove, J., Dvorak, M., Dwyer, D. A., Gallo, J. P., 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., Kohn, S., Kramer, M., Langford, T. J., Lee, J., Lee, J. H. C., Lei, R. T., Leitner, R., Leung, J. K. C., Li, F., Li, J. J., Li, Q. J., Li, S., Li, S. C., 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., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, J. C., Liu, J. L., 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., Meng, Y., Napolitano, J., Naumov, D., Naumova, E., Ochoa-Ricoux, J. P., Olshevskiy, A., Pan, H. -R., Park, J., Patton, S., Peng, J. C., Pun, C. S. J., Qi, F. Z., Qi, M., Qian, X., Raper, N., Ren, J., Reveco, C. Morales, Rosero, R., Roskovec, B., Ruan, X. C., Steiner, H., Sun, J. L., Tmej, T., 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., Worcester, E., Wu, D. R., Wu, F. L., Wu, Q., Wu, W. J., Xia, D. M., Xie, Z. Q., Xing, Z. Z., Xu, J. L., Xu, T., Xue, T., Yang, C. G., Yang, L., Yang, Y. Z., Yao, H. F., Ye, M., Yeh, M., Young, B. L., Yu, H. Z., Yu, Z. Y., Yue, B. B., Zeng, S., Zeng, Y., Zhan, L., Zhang, C., Zhang, F. Y., Zhang, H. H., Zhang, J. W., Zhang, Q. M., 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, Nuclear Experiment
Abstract

This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12~MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10~MeV is rejected with a significance of 6.2 standard deviations. A 29\% antineutrino flux deficit in the prompt energy region of 8-11~MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-$Q_{\beta}$ isotopes in commercial reactors., Comment: 7 pages, 4 figures, accepted by Physical Review Letters

Published
2022
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6. Joint Determination of Reactor Antineutrino Spectra from $^{235}$U and $^{239}$Pu Fission by Daya Bay and PROSPECT

Author

Daya Bay Collaboration, PROSPECT Collaboration, An, F. P., Andriamirado, M., Balantekin, A. B., Band, H. R., Bass, C. D., Bergeron, D. E., Berish, D., Bishai, M., Blyth, S., Bowden, N. S., Bryan, C. 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., Classen, T., Conant, A. J., Cummings, J. P., Dalager, O., Deichert, G., Delgado, A., Deng, F. S., Ding, Y. Y., Diwan, M. V., Dohnal, T., Dolinski, M. J., Dolzhikov, D., Dove, J., Dvorak, M., Dwyer, D. A., Erickson, A., Foust, B. T., Gaison, J. K., Galindo-Uribarri, A., Gallo, J. P., Gilbert, C. E., Gonchar, M., Gong, G. H., Gong, H., Grassi, M., Gu, W. Q., Guo, J. Y., Guo, L., Guo, X. H., Guo, Y. H., Guo, Z., Hackenburg, R. W., Hans, S., Hansell, A. B., He, M., Heeger, K. M., Heffron, B., Heng, Y. K., Hor, Y. K., Hsiung, Y. B., Hu, B. Z., Hu, J. R., Hu, T., Hu, Z. J., Huang, H. X., Huang, J. H., Huang, X. T., Huang, Y. B., Huber, P., Koblanski, J., Jaffe, D. E., Jayakumar, S., Jen, K. L., Ji, X. L., Ji, X. P., Johnson, R. A., Jones, D. C., Kang, L., Kettell, S. H., Kohn, S., Kramer, M., Kyzylova, O., Lane, C. E., Langford, T. J., LaRosa, J., Lee, J., Lee, J. H. C., Lei, R. T., Leitner, R., Leung, J. K. C., Li, F., Li, H. L., Li, J. J., Li, Q. J., Li, R. H., Li, S., Li, S. C., 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., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, J. C., Liu, J. L., Liu, J. X., Lu, C., Lu, H. Q., Lu, X., Luk, K. B., Ma, B. Z., Ma, X. B., Ma, X. Y., Ma, Y. Q., Mandujano, R. C., Maricic, J., Marshall, C., McDonald, K. T., McKeown, R. D., Mendenhall, M. P., Meng, Y., Meyer, A. M., Milincic, R., Mueller, P. E., Mumm, H. P., Napolitano, J., Naumov, D., Naumova, E., Neilson, R., Nguyen, T. M. T., Nikkel, J. A., Nour, S., Ochoa-Ricoux, J. P., Olshevskiy, A., Palomino, J. L., Pan, H. -R., Park, J., Patton, S., Peng, J. C., Pun, C. S. J., Pushin, D. A., Qi, F. Z., Qi, M., Qian, X., Raper, N., Ren, J., Reveco, C. Morales, Rosero, R., Roskovec, B., Ruan, X. C., Searles, M., Steiner, H., Sun, J. L., Surukuchi, P. T., Tmej, T., Treskov, K., Tse, W. -H., Tull, C. E., Tyra, M. A., Varner, R. L., Venegas-Vargas, D., 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., Weatherly, P. B., Wei, H. Y., Wei, L. H., Wen, L. J., Whisnant, K., White, C., Wilhelmi, J., Wong, H. L. H., Woolverton, A., Worcester, E., Wu, D. R., Wu, F. L., Wu, Q., Wu, W. J., Xia, D. M., Xie, Z. Q., Xing, Z. Z., Xu, H. K., Xu, J. L., Xu, T., Xue, T., Yang, C. G., Yang, L., Yang, Y. Z., Yao, H. F., Ye, M., Yeh, M., Young, B. L., Yu, H. Z., Yu, Z. Y., Yue, B. B., Zavadskyi, V., Zeng, S., Zeng, Y., Zhan, L., Zhang, C., Zhang, F. Y., Zhang, H. H., Zhang, J. W., Zhang, Q. M., Zhang, S. Q., Zhang, X., Zhang, X. T., Zhang, Y. M., Zhang, Y. X., Zhang, Y. Y., Zhang, Z. J., Zhang, Z. P., Zhang, Z. Y., Zhao, J., Zhao, R. Z., Zhou, L., Zhuang, H. L., and Zou, J. H.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

A joint determination of the reactor antineutrino spectra resulting from the fission of $^{235}$U and $^{239}$Pu has been carried out by the Daya Bay and PROSPECT collaborations. This Letter reports the level of consistency of $^{235}$U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant $^{235}$U and $^{239}$Pu isotopes and improves the uncertainty of the $^{235}$U spectral shape to about 3\%. The ${}^{235}$U and $^{239}$Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the $^{235}$U and $^{239}$Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors., Comment: 8 pages, 5 figures, Supplementary Material Included

Published
2021
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7. Model-Independent $\bar\nu_{e}$ Short-Baseline Oscillations from Reactor Spectral Ratios

Author

Gariazzo, S., Giunti, C., Laveder, M., and Li, Y. F.

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment, Nuclear Experiment
Abstract

We consider the ratio of the spectra measured in the DANSS neutrino experiment at 12.7 and 10.7~m from a nuclear reactor. These data give a new model-independent indication in favor of short-baseline $\bar\nu_{e}$ oscillations which reinforce the model-independent indication found in the late 2016 in the NEOS experiment. The combined analysis of the NEOS and DANSS spectral ratios in the framework of 3+1 active-sterile neutrino mixing favor short-baseline $\bar\nu_{e}$ oscillations with a statistical significance of $3.7\sigma$. The two mixing parameters $\sin^{2}2\vartheta_{ee}$ and $\Delta{m}^{2}_{41}$ are constrained at $2\sigma$ in a narrow-$\Delta{m}^{2}_{41}$ island at $\Delta{m}^2_{41} \simeq 1.3 \, \text{eV}^2$, with $ \sin^{2}2\vartheta_{ee} = 0.049 \pm 0.023 $ ($2\sigma$). We discuss the implications of the model-independent NEOS+DANSS analysis for the reactor and Gallium anomalies. The NEOS+DANSS model-independent determination of short-baseline $\bar\nu_{e}$ oscillations allows us to analyze the reactor rates without assumptions on the values of the main reactor antineutrino fluxes and the data of the Gallium source experiments with free detector efficiencies. The corrections to the reactor neutrino fluxes and the Gallium detector efficiencies are obtained from the fit of the data. In particular, we confirm the indication in favor of the need for a recalculation of the $^{235}\text{U}$ reactor antineutrino flux found in previous studies assuming the absence of neutrino oscillations., Comment: 10 pages; analysis improved by taking into account the uncertainties of the reactor fission fractions

Published
2018
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8. Average CsI neutron density distribution from COHERENT data

Author

Cadeddu, M., Giunti, C., Li, Y. F., and Zhang, Y. Y.

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment, Nuclear Experiment, Nuclear Theory
Abstract

Using the coherent elastic neutrino-nucleus scattering data of the COHERENT experiment, we determine for the first time the average neutron rms radius of $^{133}\text{Cs}$ and $^{127}\text{I}$. We obtain the practically model-independent value $ R_{n} = 5.5 {}^{+0.9}_{-1.1} \, \text{fm} $ using the symmetrized Fermi and Helm form factors. We also point out that the COHERENT data show a $2.3\sigma$ evidence of the nuclear structure suppression of the full coherence., Comment: 6 pages. To be published in Physical Review Letters

Published
2017
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9. Reactor Fuel Fraction Information on the Antineutrino Anomaly

Author

Giunti, C., Ji, X. P., Laveder, M., Li, Y. F., and Littlejohn, B. R.

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment, Nuclear Experiment, Nuclear Theory
Abstract

We analyzed the evolution data of the Daya Bay reactor neutrino experiment in terms of short-baseline active-sterile neutrino oscillations taking into account the theoretical uncertainties of the reactor antineutrino fluxes. We found that oscillations are disfavored at $2.6\sigma$ with respect to a suppression of the $^{235}\text{U}$ reactor antineutrino flux and at $2.5\sigma$ with respect to variations of the $^{235}\text{U}$ and $^{239}\text{Pu}$ fluxes. On the other hand, the analysis of the rates of the short-baseline reactor neutrino experiments favor active-sterile neutrino oscillations and disfavor the suppression of the $^{235}\text{U}$ flux at $3.1\sigma$ and variations of the $^{235}\text{U}$ and $^{239}\text{Pu}$ fluxes at $2.8\sigma$. We also found that both the Daya Bay evolution data and the global rate data are well-fitted with composite hypotheses including variations of the $^{235}\text{U}$ or $^{239}\text{Pu}$ fluxes in addition to active-sterile neutrino oscillations. A combined analysis of the Daya Bay evolution data and the global rate data shows a slight preference for oscillations with respect to variations of the $^{235}\text{U}$ and $^{239}\text{Pu}$ fluxes. However, the best fits of the combined data are given by the composite models, with a preference for the model with an enhancement of the $^{239}\text{Pu}$ flux and relatively large oscillations., Comment: 9 pages

Published
2017
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10. Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Author

An, F. P., Balantekin, A. B., Band, H. R., Bishai, M., Blyth, S., Cao, D., Cao, G. F., Cao, J., Chan, Y. L., Chang, J. F., Chang, Y., Chen, H. S., Chen, Q. Y., Chen, S. M., Chen, Y. X., Chen, Y., Cheng, J., Cheng, Z. K., Cherwinka, J. J., Chu, M. C., Chukanov, A., Cummings, J. P., Ding, Y. Y., Diwan, M. V., Dolgareva, M., Dove, J., Dwyer, D. A., Edwards, W. R., Gill, R., Gonchar, M., Gong, G. H., Gong, H., Grassi, M., Gu, W. Q., 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., Hsiung, Y. B., Hu, B. Z., Hu, T., Huang, E. C., Huang, H. X., Huang, X. T., Huang, Y. B., Huber, P., Huo, W., Hussain, G., Jaffe, D. E., Jen, K. L., Ji, X. P., Ji, X. L., Jiao, J. B., Johnson, R. A., Jones, D., Kang, L., Kettell, S. H., Khan, A., Kohn, S., Kramer, M., Kwan, K. K., Kwok, M. W., Langford, T. J., Lau, K., Lebanowski, L., Lee, J., Lee, J. H. C., Lei, R. T., Leitner, R., Leung, J. K. C., Li, C., Li, D. J., Li, F., Li, G. S., Li, Q. J., Li, S., Li, S. C., 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., Lin, Y. -C., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, J. L., Liu, J. C., Loh, C. W., Lu, C., Lu, H. Q., Lu, J. S., Luk, K. B., Ma, X. Y., Ma, X. B., Ma, Y. Q., Malyshkin, Y., Caicedo, D. A. Martinez, McDonald, K. T., McKeown, R. D., Mitchell, I., Nakajima, Y., Napolitano, J., Naumov, D., Naumova, E., Ngai, H. Y., 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., Qiu, R. M., Raper, N., Ren, J., Rosero, R., Roskovec, B., Ruan, X. C., Steiner, H., Stoler, P., Sun, J. L., Tang, W., Taychenachev, D., Treskov, K., Tsang, K. V., Tull, C. E., Viaux, N., Viren, B., Vorobel, V., Wang, C. H., Wang, M., Wang, N. Y., Wang, R. G., Wang, W., Wang, X., Wang, Y. F., Wang, Z., Wang, Z. M., Wei, H. Y., Wen, L. J., Whisnant, K., White, C. G., Whitehead, L., Wise, T., Wong, H. L. H., Wong, S. C. F., Worcester, E., Wu, C. -H., Wu, Q., Wu, W. J., Xia, D. M., Xia, J. K., Xing, Z. Z., Xu, J. L., Xu, Y., Xue, T., Yang, C. G., Yang, H., Yang, L., Yang, M. S., Yang, M. T., Yang, Y. Z., Ye, M., Ye, Z., Yeh, M., Young, B. L., Yu, Z. Y., Zeng, S., Zhan, L., Zhang, C., Zhang, C. C., Zhang, H. H., Zhang, J. W., Zhang, Q. M., Zhang, R., Zhang, X. T., Zhang, Y. M., Zhang, Y. X., Zhang, Z. J., Zhang, Z. Y., Zhang, Z. P., Zhao, J., Zhou, L., Zhuang, H. L., and Zou, J. H.

Subjects
High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW$_{\textrm{th}}$ reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective $^{239}$Pu fission fractions, $F_{239}$, from 0.25 to 0.35, Daya Bay measures an average IBD yield, $\bar{\sigma}_f$, of $(5.90 \pm 0.13) \times 10^{-43}$ cm$^2$/fission and a fuel-dependent variation in the IBD yield, $d\sigma_f/dF_{239}$, of $(-1.86 \pm 0.18) \times 10^{-43}$ cm$^2$/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the $^{239}$Pu fission fraction at 10 standard deviations. The variation in IBD yield was found to be energy-dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1$\sigma$. This discrepancy indicates that an overall deficit in measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes $^{235}$U, $^{239}$Pu, $^{238}$U, and $^{241}$Pu. Based on measured IBD yield variations, yields of $(6.17 \pm 0.17)$ and $(4.27 \pm 0.26) \times 10^{-43}$ cm$^2$/fission have been determined for the two dominant fission parent isotopes $^{235}$U and $^{239}$Pu. A 7.8% discrepancy between the observed and predicted $^{235}$U yield suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly., Comment: 7 pages, 5 figures

Published
2017
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11. Measurement of electron antineutrino oscillation based on 1230 days of operation of the Daya Bay experiment

Author

Daya Bay Collaboration, An, F. P., Balantekin, A. B., Band, H. R., Bishai, M., Blyth, S., Cao, D., Cao, G. F., Cao, J., Cen, W. R., Chan, Y. L., Chang, J. F., Chang, L. C., Chang, Y., Chen, H. S., Chen, Q. Y., Chen, S. M., Chen, Y. X., Chen, Y., Cheng, J. -H., Cheng, J., Cheng, Y. P., Cheng, Z. K., Cherwinka, J. J., Chu, M. C., Chukanov, A., Cummings, J. P., de Arcos, J., Deng, Z. Y., Ding, X. F., Ding, Y. Y., Diwan, M. V., Dolgareva, M., Dove, J., Dwyer, D. A., Edwards, W. R., Gill, R., Gonchar, M., Gong, G. H., Gong, H., Grassi, M., Gu, W. Q., Guan, M. Y., Guo, L., Guo, X. H., Guo, Z., Hackenburg, R. W., Han, R., Hans, S., He, M., Heeger, K. M., Heng, Y. K., Higuera, A., Hor, Y. K., Hsiung, Y. B., Hu, B. Z., Hu, T., Hu, W., Huang, E. C., Huang, H. X., Huang, X. T., Huber, P., Huo, W., Hussain, G., Jaffe, D. E., Jaffke, P., Jen, K. L., Jetter, S., Ji, X. P., Ji, X. L., Jiao, J. B., Johnson, R. A., Jones, D., Joshi, J., Kang, L., Kettell, S. H., Kohn, S., Kramer, M., Kwan, K. K., Kwok, M. W., Kwok, T., Langford, T. J., Lau, K., Lebanowski, L., Lee, J., Lee, J. H. C., Lei, R. T., Leitner, R., Leung, J. K. C., Li, C., Li, D. J., Li, F., Li, G. S., Li, Q. J., Li, S., Li, S. C., Li, W. D., Li, X. N., Li, Y. F., Li, Z. B., Liang, H., Lin, C. J., Lin, G. L., Lin, S., Lin, S. K., Lin, Y. -C., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, D. W., Liu, J. L., Liu, J. C., Loh, C. W., Lu, C., Lu, H. Q., Lu, J. S., Luk, K. B., Lv, Z., Ma, Q. M., Ma, X. Y., Ma, X. B., Ma, Y. Q., Malyshkin, Y., Caicedo, D. A. Martinez, McDonald, K. T., McKeown, R. D., Mitchell, I., Mooney, M., Nakajima, Y., Napolitano, J., Naumov, D., Naumova, E., Ngai, H. Y., Ning, Z., 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, G. X., Sun, J. L., Tang, W., Taychenachev, D., Treskov, K., Tsang, K. V., Tull, C. E., Viaux, N., Viren, B., Vorobel, V., Wang, C. H., Wang, M., Wang, N. Y., Wang, R. G., Wang, W., Wang, X., Wang, Y. F., Wang, Z., Wang, Z. M., Wei, H. Y., Wen, L. J., Whisnant, K., White, C. G., Whitehead, L., Wise, T., Wong, H. L. H., Wong, S. C. F., Worcester, E., Wu, C. -H., Wu, Q., Wu, W. J., Xia, D. M., Xia, J. K., Xing, Z. Z., Xu, J. Y., Xu, J. L., Xu, Y., Xue, T., Yang, C. G., Yang, H., Yang, L., Yang, M. S., Yang, M. T., Ye, M., Ye, Z., Yeh, M., Young, B. L., Yu, Z. Y., Zeng, S., Zhan, L., Zhang, C., Zhang, H. H., Zhang, J. W., Zhang, Q. M., Zhang, X. T., Zhang, Y. M., Zhang, Y. X., Zhang, Z. J., Zhang, Z. Y., Zhang, Z. P., Zhao, J., Zhao, Q. W., Zhao, Y. B., Zhong, W. L., Zhou, L., Zhou, N., Zhuang, H. L., and Zou, J. H.

Subjects
High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

A measurement of electron antineutrino oscillation by the Daya Bay Reactor Neutrino Experiment is described in detail. Six 2.9-GW$_{\rm th}$ nuclear power reactors of the Daya Bay and Ling Ao nuclear power facilities served as intense sources of $\overline{\nu}_{e}$'s. Comparison of the $\overline{\nu}_{e}$ rate and energy spectrum measured by antineutrino detectors far from the nuclear reactors ($\sim$1500-1950 m) relative to detectors near the reactors ($\sim$350-600 m) allowed a precise measurement of $\overline{\nu}_{e}$ disappearance. More than 2.5 million $\overline{\nu}_{e}$ inverse beta decay interactions were observed, based on the combination of 217 days of operation of six antineutrino detectors (Dec. 2011--Jul. 2012) with a subsequent 1013 days using the complete configuration of eight detectors (Oct. 2012--Jul. 2015). The $\overline{\nu}_{e}$ rate observed at the far detectors relative to the near detectors showed a significant deficit, $R=0.949 \pm 0.002(\mathrm{stat.}) \pm 0.002(\mathrm{syst.})$. The energy dependence of $\overline{\nu}_{e}$ disappearance showed the distinct variation predicted by neutrino oscillation. Analysis using an approximation for the three-flavor oscillation probability yielded the flavor-mixing angle $\sin^22\theta_{13}=0.0841 \pm 0.0027(\mathrm{stat.}) \pm 0.0019(\mathrm{syst.})$ and the effective neutrino mass-squared difference of $\left|{\Delta}m^2_{\mathrm{ee}}\right|=(2.50 \pm 0.06(\mathrm{stat.}) \pm 0.06(\mathrm{syst.})) \times 10^{-3}\ {\rm eV}^2$. Analysis using the exact three-flavor probability found ${\Delta}m^2_{32}=(2.45 \pm 0.06(\mathrm{stat.}) \pm 0.06(\mathrm{syst.})) \times 10^{-3}\ {\rm eV}^2$ assuming the normal neutrino mass hierarchy and ${\Delta}m^2_{32}=(-2.56 \pm 0.06(\mathrm{stat.}) \pm 0.06(\mathrm{syst.})) \times 10^{-3}\ {\rm eV}^2$ for the inverted hierarchy., Comment: 44 pages, 44 figures

Published
2016
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12. Improved Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Author

An, F. P., Balantekin, A. B., Band, H. R., Bishai, M., Blyth, S., Cao, D., Cao, G. F., Cao, J., Cen, W. R., Chan, Y. L., Chang, J. F., Chang, L. C., Chang, Y., Chen, H. S., Chen, Q. Y., Chen, S. M., Chen, Y. X., Chen, Y., Cheng, J. -H., Cheng, J., Cheng, Y. P., Cheng, Z. K., Cherwinka, J. J., Chu, M. C., Chukanov, A., Cummings, J. P., de Arcos, J., Deng, Z. Y., Ding, X. F., Ding, Y. Y., Diwan, M. V., Dolgareva, M., Dove, J., Dwyer, D. A., Edwards, W. R., Gill, R., Gonchar, M., Gong, G. H., Gong, H., Grassi, M., Gu, W. Q., Guan, M. Y., Guo, L., Guo, R. P., Guo, X. H., Guo, Z., Hackenburg, R. W., Han, R., Hans, S., He, M., Heeger, K. M., Heng, Y. K., Higuera, A., Hor, Y. K., Hsiung, Y. B., Hu, B. Z., Hu, T., Hu, W., Huang, E. C., Huang, H. X., Huang, X. T., Huber, P., Huo, W., Hussain, G., Jaffe, D. E., Jaffke, P., Jen, K. L., Jetter, S., Ji, X. P., Ji, X. L., Jiao, J. B., Johnson, R. A., Jones, D., Joshi, J., Kang, L., Kettell, S. H., Kohn, S., Kramer, M., Kwan, K. K., Kwok, M. W., Kwok, T., Langford, T. J., Lau, K., Lebanowski, L., Lee, J., Lee, J. H. C., Lei, R. T., Leitner, R., Li, C., Li, D. J., Li, F., Li, G. S., Li, Q. J., Li, S., Li, S. C., Li, W. D., Li, X. N., Li, Y. F., Li, Z. B., Liang, H., Lin, C. J., Lin, G. L., Lin, S., Lin, S. K., Lin, Y. -C., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, D. W., Liu, J. L., Liu, J. C., Loh, C. W., Lu, C., Lu, H. Q., Lu, J. S., Luk, K. B., Lv, Z., Ma, Q. M., Ma, X. Y., Ma, X. B., Ma, Y. Q., Malyshkin, Y., Caicedo, D. A. Martinez, McDonald, K. T., McKeown, R. D., Mitchell, I., Mooney, M., Nakajima, Y., Napolitano, J., Naumov, D., Naumova, E., Ngai, H. Y., Ning, Z., 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, G. X., Sun, J. L., Tang, W., Taychenachev, D., Treskov, K., Tsang, K. V., Tull, C. E., Viaux, N., Viren, B., Vorobel, V., Wang, C. H., Wang, M., Wang, N. Y., Wang, R. G., Wang, W., Wang, X., Wang, Y. F., Wang, Z., Wang, Z. M., Wei, H. Y., Wen, L. J., Whisnant, K., White, C. G., Whitehead, L., Wise, T., Wong, H. L. H., Wong, S. C. F., Worcester, E., Wu, C. -H., Wu, Q., Wu, W. J., Xia, D. M., Xia, J. K., Xing, Z. Z., Xu, J. Y., Xu, J. L., Xu, Y., Xue, T., Yang, C. G., Yang, H., Yang, L., Yang, M. S., Yang, M. T., Ye, M., Ye, Z., Yeh, M., Young, B. L., Yu, Z. Y., Zeng, S., Zhan, L., Zhang, C., Zhang, H. H., Zhang, J. W., Zhang, Q. M., Zhang, X. T., Zhang, Y. M., Zhang, Y. X., Zhang, Z. J., Zhang, Z. Y., Zhang, Z. P., Zhao, J., Zhao, Q. W., Zhao, Y. B., Zhong, W. L., Zhou, L., Zhou, N., Zhuang, H. L., and Zou, J. H.

Subjects
High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The antineutrinos were generated by six 2.9~GW$_{\mathrm{th}}$ nuclear reactors and detected by eight antineutrino detectors deployed in two near (560~m and 600~m flux-weighted baselines) and one far (1640~m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be $0.946\pm0.020$ ($0.992\pm0.021$) for the Huber+Mueller (ILL+Vogel) model. A 2.9~$\sigma$ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4-6~MeV was found in the measured spectrum, with a local significance of 4.4~$\sigma$. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions., Comment: version published in Chinese Physics C

Published
2016
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13. Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Author

Daya Bay Collaboration, An, F. P., Balantekin, A. B., Band, H. R., Bishai, M., Blyth, S., Butorov, I., Cao, D., Cao, G. F., Cao, J., Cen, W. R., Chan, Y. L., Chang, J. F., Chang, L. C., Chang, Y., Chen, H. S., Chen, Q. Y., Chen, S. M., Chen, Y. X., Chen, Y., Cheng, J. H., Cheng, J., Cheng, Y. P., Cherwinka, J. J., Chu, M. C., Cummings, J. P., de Arcos, J., Deng, Z. Y., Ding, X. F., Ding, Y. Y., Diwan, M. V., Dove, J., Draeger, E., Dwyer, D. A., Edwards, W. R., Ely, S. R., Gill, R., Gonchar, M., Gong, G. H., Gong, H., Grassi, M., Gu, W. Q., Guan, M. Y., Guo, L., Guo, X. H., Hackenburg, R. W., Han, R., Hans, S., He, M., Heeger, K. M., Heng, Y. K., Higuera, A., Hor, Y. K., Hsiung, Y. B., Hu, B. Z., Hu, L. M., Hu, L. J., Hu, T., Hu, W., Huang, E. C., Huang, H. X., Huang, X. T., Huber, P., Hussain, G., Jaffe, D. E., Jaffke, P., Jen, K. L., Jetter, S., Ji, X. P., Ji, X. L., Jiao, J. B., Johnson, R. A., Kang, L., Kettell, S. H., Kohn, S., Kramer, M., Kwan, K. K., Kwok, M. W., Kwok, T., Langford, T. J., Lau, K., Lebanowski, L., Lee, J., Lei, R. T., Leitner, R., Leung, K. Y., Leung, J. K. C., Lewis, C. A., Li, D. J., Li, F., Li, G. S., Li, Q. J., Li, S. C., Li, W. D., Li, X. N., Li, X. Q., Li, Y. F., Li, Z. B., Liang, H., Lin, C. J., Lin, G. L., Lin, P. Y., Lin, S. K., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, D. W., Liu, H., Liu, J. L., Liu, J. C., Liu, S. S., Lu, C., Lu, H. Q., Lu, J. S., Luk, K. B., Ma, Q. M., Ma, X. Y., Ma, X. B., Ma, Y. Q., Caicedo, D. A. Martinez, McDonald, K. T., McKeown, R. D., Meng, Y., Mitchell, I., Kebwaro, J. Monari, Nakajima, Y., Napolitano, J., Naumov, D., Naumova, E., Ngai, H. Y., Ning, Z., Ochoa-Ricoux, J. P., Olshevski, A., Pan, H. -R., Park, J., Patton, S., Pec, V., Peng, J. C., Piilonen, L. E., Pinsky, L., Pun, C. S. J., Qi, F. Z., Qi, M., Qian, X., Raper, N., Ren, B., Ren, J., Rosero, R., Roskovec, B., Ruan, X. C., Shao, B. B., Steiner, H., Sun, G. X., Sun, J. L., Tang, W., Taychenachev, D., Tsang, K. V., Tull, C. E., Tung, Y. C., Viaux, N., Viren, B., Vorobel, V., Wang, C. H., Wang, M., Wang, N. Y., Wang, R. G., Wang, W., Wang, W. W., Wang, X., Wang, Y. F., Wang, Z., Wang, Z. M., Wei, H. Y., Wen, L. J., Whisnant, K., White, C. G., Whitehead, L., Wise, T., Wong, H. L. H., Wong, S. C. F., Worcester, E., Wu, Q., Xia, D. M., Xia, J. K., Xia, X., Xing, Z. Z., Xu, J. Y., Xu, J. L., Xu, J., Xu, Y., Xue, T., Yan, J., Yang, C. G., Yang, L., Yang, M. S., Yang, M. T., Ye, M., Yeh, M., Young, B. L., Yu, G. Y., Yu, Z. Y., Zang, S. L., Zhan, L., Zhang, C., Zhang, H. H., Zhang, J. W., Zhang, Q. M., Zhang, Y. M., Zhang, Y. X., Zhang, Z. J., Zhang, Z. Y., Zhang, Z. P., Zhao, J., Zhao, Q. W., Zhao, Y. F., Zhao, Y. B., Zheng, L., Zhong, W. L., Zhou, L., Zhou, N., Zhuang, H. L., and Zou, J. H.

Subjects
High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9~GW$_{th}$ nuclear reactors with six detectors deployed in two near (effective baselines 512~m and 561~m) and one far (1,579~m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296,721 and 41,589 inverse beta decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55 $\pm$ 0.04) $\times$ 10$^{-18}$~cm$^2$/GW/day or (5.92 $\pm$ 0.14) $\times$ 10$^{-43}$~cm$^2$/fission. This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is $0.946\pm0.022$ ($0.991\pm0.023$) relative to the flux predicted with the Huber+Mueller (ILL+Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2$\sigma$ over the full energy range with a local significance of up to $\sim$4$\sigma$ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

Published
2015
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14. A new measurement of antineutrino oscillation with the full detector configuration at Daya Bay

Author

Daya Bay Collaboration, An, F. P., Balantekin, A. B., Band, H. R., Bishai, M., Blyth, S., Butorov, I., Cao, G. F., Cao, J., Cen, W. R., Chan, Y. L., Chang, J. F., Chang, L. C., Chang, Y., Chen, H. S., Chen, Q. Y., Chen, S. M., Chen, Y. X., Chen, Y., Cheng, J. H., Cheng, J., Cheng, Y. P., Cherwinka, J. J., Chu, M. C., Cummings, J. P., de Arcos, J., Deng, Z. Y., Ding, X. F., Ding, Y. Y., Diwan, M. V., Draeger, E., Dwyer, D. A., Edwards, W. R., Ely, S. R., Gill, R., Gonchar, M., Gong, G. H., Gong, H., Grassi, M., Gu, W. Q., Guan, M. Y., Guo, L., Guo, X. H., Hackenburg, R. W., Han, R., Hans, S., He, M., Heeger, K. M., Heng, Y. K., Hor, Y. K., Hsiung, Y. B., Hu, B. Z., Hu, L. M., Hu, L. J., Hu, T., Hu, W., Huang, E. C., Huang, H. X., Huang, X. T., Huber, P., Hussain, G., Jaffe, D. E., Jaffke, P., Jen, K. L., Jetter, S., Ji, X. P., Ji, X. L., Jiao, J. B., Johnson, R. A., Kang, L., Kettell, S. H., Kramer, M., Kwan, K. K., Kwok, M. W., Kwok, T., Langford, T. J., Lau, K., Lebanowski, L., Lee, J., Lei, R. T., Leitner, R., Leung, A., Leung, J. K. C., Lewis, C. A., Li, D. J., Li, F., Li, G. S., Li, Q. J., Li, S. C., Li, W. D., Li, X. N., Li, X. Q., Li, Y. F., Li, Z. B., Liang, H., Lin, C. J., Lin, G. L., Lin, P. Y., Lin, S. K., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, D. W., Liu, H., Liu, J. L., Liu, J. C., Liu, S. S., Lu, C., Lu, H. Q., Lu, J. S., Luk, K. B., Ma, Q. M., Ma, X. Y., Ma, X. B., Ma, Y. Q., McDonald, K. T., McKeown, R. D., Meng, Y., Mitchell, I., Kebwaro, J. Monari, Nakajima, Y., Napolitano, J., Naumov, D., Naumova, E., Ngai, H. Y., Ning, Z., Ochoa-Ricoux, J. P., Olshevski, A., Patton, S., Pec, V., Peng, J. C., Piilonen, L. E., Pinsky, L., Pun, C. S. J., Qi, F. Z., Qi, M., Qian, X., Raper, N., Ren, B., Ren, J., Rosero, R., Roskovec, B., Ruan, X. C., Shao, B. B., Steiner, H., Sun, G. X., Sun, J. L., Tang, W., Themann, H., Tsang, K. V., Tull, C. E., Tung, Y. C., Viaux, N., Viren, B., Vorobel, V., Wang, C. H., Wang, M., Wang, N. Y., Wang, R. G., Wang, W., Wang, W. W., Wang, X., Wang, Y. F., Wang, Z., Wang, Z. M., Wei, H. Y., Wen, L. J., Whisnant, K., White, C. G., Whitehead, L., Wise, T., Wong, H. L. H., Wong, S. C. F., Worcester, E., Wu, Q., Xia, D. M., Xia, J. K., Xia, X., Xing, Z. Z., Xu, J. Y., Xu, J. L., Xu, J., Xu, Y., Xue, T., Yan, J., Yang, C. G., Yang, L., Yang, M. S., Yang, M. T., Ye, M., Yeh, M., Yeh, Y. S., Young, B. L., Yu, G. Y., Yu, Z. Y., Zang, S. L., Zhan, L., Zhang, C., Zhang, H. H., Zhang, J. W., Zhang, Q. M., Zhang, Y. M., Zhang, Y. X., Zhang, Z. J., Zhang, Z. Y., Zhang, Z. P., Zhao, J., Zhao, Q. W., Zhao, Y. F., Zhao, Y. B., Zheng, L., Zhong, W. L., Zhou, L., Zhou, N., Zhuang, H. L., and Zou, J. H.

Subjects
High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

We report a new measurement of electron antineutrino disappearance using the fully-constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9$\times$10$^5$ GW$_{\rm th}$-ton-days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six $^{241}$Am-$^{13}$C radioactive calibration sources reduced the background by a factor of two for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of $\sin^{2}2\theta_{13}$ and $|\Delta m^2_{ee}|$ were halved as a result of these improvements. Analysis of the relative antineutrino rates and energy spectra between detectors gave $\sin^{2}2\theta_{13} = 0.084\pm0.005$ and $|\Delta m^{2}_{ee}|= (2.42\pm0.11) \times 10^{-3}$ eV$^2$ in the three-neutrino framework., Comment: Updated to match final published version

Published
2015
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15. Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay

Author

Daya Bay Collaboration, An, F. P., Balantekin, A. B., Band, H. R., Beriguete, W., Bishai, M., Blyth, S., Brown, R. L., Butorov, I., Cao, G. F., Cao, J., Carr, R., Chan, Y. L., Chang, J. F., Chang, Y., Chasman, C., Chen, H. S., Chen, H. Y., Chen, S. J., Chen, S. M., Chen, X. C., Chen, X. H., Chen, Y., Chen, Y. X., Cheng, Y. P., Cherwinka, J. J., Chu, M. C., Cummings, J. P., de Arcos, J., Deng, Z. Y., Ding, Y. Y., Diwan, M. V., Draeger, E., Du, X. F., Dwyer, D. A., Edwards, W. R., Ely, S. R., Fu, J. Y., Ge, L. Q., Gill, R., Gonchar, M., Gong, G. H., Gong, H., Gornushkin, Y. A., Gu, W. Q., Guan, M. Y., Guo, X. H., Hackenburg, R. W., Hahn, R. L., Han, G. H., Hans, S., He, M., Heeger, K. M., Heng, Y. K., Hinrichs, P., Hor, yk., Hsiung, Y. B., Hu, B. Z., Hu, L. J., Hu, L. M., Hu, T., Hu, W., Huang, E. C., Huang, H. X., Huang, H. Z., Huang, X. T., Huber, P., Hussain, G., Isvan, Z., Jaffe, D. E., Jaffke, P., Jetter, S., Ji, X. L., Ji, X. P., Jiang, H. J., Jiao, J. B., Johnson, R. A., Kang, L., Kettell, S. H., Kramer, M., Kwan, K. K., Kwok, M. W., Kwok, T., Lai, W. C., Lai, W. H., Lau, K., Lebanowski, L., Lee, J., Lei, R. T., Leitner, R., Leung, A., Leung, J. K. C., Lewis, C. A., Li, D. J., Li, F., Li, G. S., Li, Q. 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. K., Lin, Y. C., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, D. W., Liu, H., Liu, J. C., Liu, J. L., Liu, S. S., Liu, Y. B., Lu, C., Lu, H. Q., Luk, K. B., Ma, Q. M., Ma, X. B., Ma, X. Y., Ma, Y. Q., McDonald, K. T., McFarlane, M. C., McKeown, R. D., Meng, Y., Mitchell, I., Nakajima, Y., Napolitano, J., Naumov, D., Naumova, E., Nemchenok, I., Ngai, H. Y., Ngai, W. K., Ning, Z., Ochoa-Ricoux, J. P., Olshevski, A., Patton, S., Pec, V., Peng, J. C., Piilonen, L. E., Pinsky, L., Pun, C. S. J., Qi, F. Z., Qi, M., Qian, X., Raper, N., Ren, B., Ren, J., Rosero, R., Roskovec, B., Ruan, X. C., Shao, B. B., Steiner, H., Sun, G. X., Sun, J. L., Tam, Y. H., Tanaka, H. K., Tang, X., Themann, H., Trentalange, S., Tsai, O., Tsang, K. V., Tsang, R. H. M., Tull, C. E., Tung, Y. C., Viren, B., Vorobel, V., Wang, C. H., Wang, L. S., Wang, L. Y., Wang, L. Z., Wang, M., Wang, N. Y., Wang, R. G., Wang, W., Wang, W. W., Wang, X., Wang, Y. F., Wang, Z., Wang, Z. M., Webber, D. M., Wei, H., Wei, Y. D., Wen, L. J., Whisnant, K., White, C. G., Whitehead, L., Wise, T., Wong, H. L. H., Wong, S. C. F., Worcester, E., Wu, Q., Xia, D. M., Xia, J. K., Xia, X., Xing, Z. Z., Xu, J., Xu, J. L., Xu, J. Y., Xu, Y., Xue, T., Yan, J., Yang, C. G., Yang, L., Yang, M. S., Ye, M., Yeh, M., Yeh, Y. S., Young, B. L., Yu, G. Y., Yu, J. Y., Yu, Z. Y., Zang, S. L., Zhan, L., Zhang, C., Zhang, F. H., Zhang, J. W., Zhang, Q. M., Zhang, S. H., Zhang, Y. C., Zhang, Y. H., Zhang, Y. M., Zhang, Y. X., Zhang, Z. J., Zhang, Z. P., Zhang, Z. Y., Zhao, J., Zhao, Q. W., Zhao, Y. B., Zheng, L., Zhong, W. L., Zhou, L., Zhou, Z. Y., Zhuang, H. L., and Zou, J. H.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

A measurement of the energy dependence of antineutrino disappearance at the Daya Bay Reactor Neutrino Experiment is reported. Electron antineutrinos ($\overline{\nu}_{e}$) from six $2.9$ GW$_{\rm th}$ reactors were detected with six detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41589 (203809 and 92912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude $\sin^{2}2\theta_{13} = 0.090^{+0.008}_{-0.009} $ and the first direct measurement of the $\overline{\nu}_{e}$ mass-squared difference $|\Delta m^{2}_{ee}|= (2.59_{-0.20}^{+0.19}) \times 10^{-3}\ {\rm eV}^2 $ is obtained using the observed $\overline{\nu}_{e}$ rates and energy spectra in a three-neutrino framework. This value of $|\Delta m^{2}_{ee}|$ is consistent with $|\Delta m^{2}_{\mu\mu}|$ measured by muon neutrino disappearance, supporting the three-flavor oscillation model., Comment: As accepted for publication by Phys. Rev. Lett. including ancillary table

Published
2013
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16. Light Sterile Neutrinos: A White Paper

Author

Abazajian, K. N., Acero, M. A., Agarwalla, S. K., Aguilar-Arevalo, A. A., Albright, C. H., Antusch, S., Arguelles, C. A., Balantekin, A. B., Barenboim, G., Barger, V., Bernardini, P., Bezrukov, F., Bjaelde, O. E., Bogacz, S. A., Bowden, N. S., Boyarsky, A., Bravar, A., Berguno, D. Bravo, Brice, S. J., Bross, A. D., Caccianiga, B., Cavanna, F., Chun, E. J., Cleveland, B. T., Collin, A. P., Coloma, P., Conrad, J. M., Cribier, M., Cucoanes, A. S., D'Olivo, J. C., Das, S., de Gouvea, A., Derbin, A. V., Dharmapalan, R., Diaz, J. S., Ding, X. J., Djurcic, Z., Donini, A., Duchesneau, D., Ejiri, H., Elliott, S. R., Ernst, D. J., Esmaili, A., Evans, J. J., Fernandez-Martinez, E., Figueroa-Feliciano, E., Fleming, B. T., Formaggio, J. A., Franco, D., Gaffiot, J., Gandhi, R., Gao, Y., Garvey, G. T., Gavrin, V. N., Ghoshal, P., Gibin, D., Giunti, C., Gninenko, S. N., Gorbachev, V. V., Gorbunov, D. S., Guenette, R., Guglielmi, A., Halzen, F., Hamann, J., Hannestad, S., Haxton, W., Heeger, K. M., Henning, R., Hernandez, P., Huber, P., Huelsnitz, W., Ianni, A., Ibragimova, T. V., Karadzhov, Y., Karagiorgi, G., Keefer, G., Kim, Y. D., Kopp, J., Kornoukhov, V. N., Kusenko, A., Kyberd, P., Langacker, P., Lasserre, Th., Laveder, M., Letourneau, A., Lhuillier, D., Li, Y. F., Lindner, M., Link, J. M., Littlejohn, B. L., Lombardi, P., Long, K., Lopez-Pavon, J., Louis, W. C., Ludhova, L., Lykken, J. D., Machado, P. A. N., Maltoni, M., Mann, W. A., Marfatia, D., Mariani, C., Matveev, V. A., Mavromatos, N. E., Melchiorri, A., Meloni, D., Mena, O., Mention, G., Merle, A., Meroni, E., Mezzetto, M., Mills, G. B., Minic, D., Miramonti, L., Mohapatra, D., Mohapatra, R. N., Montanari, C., Mori, Y., Mueller, Th. A., Mumm, H. P., Muratova, V., Nelson, A. E., Nico, J. S., Noah, E., Nowak, J., Smirnov, O. Yu., Obolensky, M., Pakvasa, S., Palamara, O., Pallavicini, M., Pascoli, S., Patrizii, L., Pavlovic, Z., Peres, O. L. G., Pessard, H., Pietropaolo, F., Pitt, M. L., Popovic, M., Pradler, J., Ranucci, G., Ray, H., Razzaque, S., Rebel, B., Robertson, R. G. H., Rodejohann, W., Rountree, S. D., Rubbia, C., Ruchayskiy, O., Sala, P. R., Scholberg, K., Schwetz, T., Shaevitz, M. H., Shaposhnikov, M., Shrock, R., Simone, S., Skorokhvatov, M., Sorel, M., Sousa, A., Spergel, D. N., Spitz, J., Stanco, L., Stancu, I., Suzuki, A., Takeuchi, T., Tamborra, I., Tang, J., Testera, G., Tian, X. C., Tonazzo, A., Tunnell, C. D., Van de Water, R. G., Verde, L., Veretenkin, E. P., Vignoli, C., Vivier, M., Vogelaar, R. B., Wascko, M. O., Wilkerson, J. F., Winter, W., Wong, Y. Y. Y., Yanagida, T. T., Yasuda, O., Yeh, M., Yermia, F., Yokley, Z. W., Zeller, G. P., Zhan, L., and Zhang, H.

Subjects
High Energy Physics - Phenomenology, Astrophysics - Cosmology and Extragalactic Astrophysics, High Energy Physics - Experiment, Nuclear Experiment, Nuclear Theory
Abstract

This white paper addresses the hypothesis of light sterile neutrinos based on recent anomalies observed in neutrino experiments and the latest astrophysical data.

Published
2012

17. First Measurement of High-Energy Reactor Antineutrinos at Daya Bay

Author

An, F. P., Bai, W. D., Balantekin, A. B., Bishai, M., Blyth, S., Cao, G. F., Cao, J., Chang, J. F., Chang, Y., Chen, H. S., Chen, H. Y., Chen, S. M., Chen, Y., Chen, Y. X., Cheng, J., Cheng, Z. K., Cherwinka, J. J., Chu, M. C., Cummings, J. P., Dalager, O., Deng, F. S., Ding, Y. Y., Diwan, M. V., Dohnal, T., Dolzhikov, D., Dove, J., Dwyer, D. A., Gallo, J. P., 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., Hor, Y. K., Hsiung, Y. B., Hu, B. Z., Hu, J. R., Hu, T., Hu, Z. J., Huang, H. X., Huang, J. H., 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., Kohn, S., Kramer, M., Langford, T. J., Lee, J., Lee, J. H. C., Lei, R. T., Leitner, R., Leung, J. K. C., Li, F., Li, H. L., Li, J. J., Li, Q. J., Li, R. H., Li, S., Li, S. C., 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., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, J. C., Liu, J. L., Liu, J. X., Lu, C., Lu, H. Q., Luk, K. B., Ma, B. Z., Ma, X. B., Ma, X. Y., Ma, Y. Q., Mandujano, R. C., Marshall, C., McDonald, K. T., McKeown, R. D., Meng, Y., Napolitano, J., Naumov, D., Naumova, E., Nguyen, T. M. T., Ochoa-Ricoux, J. P., Olshevskiy, A., Pan, H.-R., Park, J., Patton, S., Peng, J. C., Pun, C. S. J., Qi, F. Z., Qi, M., Qian, X., Raper, N., Ren, J., Morales Reveco, C., Rosero, R., Roskovec, B., Ruan, X. C., Steiner, H., Sun, J. L., Tmej, T., 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., Worcester, E., Wu, D. R., Wu, Q., Wu, W. J., Xia, D. M., Xie, Z. Q., Xing, Z. Z., Xu, H. K., Xu, J. L., Xu, T., Xue, T., Yang, C. G., Yang, L., Yang, Y. Z., Yao, H. F., Ye, M., Yeh, M., Young, B. L., Yu, H. Z., Yu, Z. Y., Yue, B. B., Zavadskyi, V., Zeng, S., Zeng, Y., Zhan, L., Zhang, C., Zhang, F. Y., Zhang, H. H., Zhang, J. L., Zhang, J. W., Zhang, Q. M., Zhang, S. Q., Zhang, X. T., Zhang, Y. M., Zhang, Y. X., Zhang, Y. Y., Zhang, Z. J., Zhang, Z. P., Zhang, Z. Y., Zhao, J., Zhao, R. Z., Zhou, L., Zhuang, H. L., and Zou, J. H.

Subjects
High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, General Physics and Astronomy, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, High Energy Physics - Experiment, Physics::Geophysics
Abstract

This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12~MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10~MeV is rejected with a significance of 6.2 standard deviations. A 29\% antineutrino flux deficit in the prompt energy region of 8-11~MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-$Q_{\beta}$ isotopes in commercial reactors., Comment: 7 pages, 4 figures, accepted by Physical Review Letters

Published
2022

18. Extraction of the $^{235}$U and $^{239}$Pu Antineutrino Spectra at Daya Bay

Author

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

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