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Main Author: Huang, Guihong
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.16915
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author Huang, Guihong
author_facet Huang, Guihong
contents Recently, the JUNO experiment published its measurement of the solar neutrino oscillation parameters $Δm^2_{21}$ and $\sin^2θ_{12}$ based on 59 days of data, with central values differing by $0.2σ$ from those released by the KamLAND experiment in 2013. Meanwhile, short-baseline reactor neutrino oscillation experiments such as Daya Bay, RENO, and Double Chooz have observed significant deviations between the measured antineutrino spectrum and the Huber-Müller model prediction around 5~MeV. To further investigate the impact of these deviations on the measurement of reactor neutrino oscillation parameters, we construct a global analysis framework that is weakly dependent on the reactor antineutrino flux model. This framework is based on the independently measured $^{235}\mathrm{U}$ and $^{239}\mathrm{Pu}$ fission antineutrino spectra from the Daya Bay experiment, combined with the public data from KamLAND. First, using the Huber-Müller model, we successfully reproduce the KamLAND 2013 results to within $0.1σ$. Then, replacing the Huber-Müller model with the Daya Bay measured antineutrino spectra in a combined analysis, we find that the best-fit value of the mass-squared difference $Δm^2_{21}$ decreases from $7.53^{+0.17}_{-0.16}\times10^{-5}\,\mathrm{eV^2}$ to $7.50^{+0.19}_{-0.18}\times10^{-5}\,\mathrm{eV^2}$, while the best-fit value of the mixing angle $\tan^2θ_{12}$ also shows a decreasing trend. This result is in better agreement with the latest JUNO measurement, suggesting that differences in the predicted reactor antineutrino spectra may be an important cause of the tension between the two experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2605_16915
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Global Fit of KamLAND Data and the Daya Bay Antineutrino Energy Spectrum
Huang, Guihong
High Energy Physics - Experiment
Recently, the JUNO experiment published its measurement of the solar neutrino oscillation parameters $Δm^2_{21}$ and $\sin^2θ_{12}$ based on 59 days of data, with central values differing by $0.2σ$ from those released by the KamLAND experiment in 2013. Meanwhile, short-baseline reactor neutrino oscillation experiments such as Daya Bay, RENO, and Double Chooz have observed significant deviations between the measured antineutrino spectrum and the Huber-Müller model prediction around 5~MeV. To further investigate the impact of these deviations on the measurement of reactor neutrino oscillation parameters, we construct a global analysis framework that is weakly dependent on the reactor antineutrino flux model. This framework is based on the independently measured $^{235}\mathrm{U}$ and $^{239}\mathrm{Pu}$ fission antineutrino spectra from the Daya Bay experiment, combined with the public data from KamLAND. First, using the Huber-Müller model, we successfully reproduce the KamLAND 2013 results to within $0.1σ$. Then, replacing the Huber-Müller model with the Daya Bay measured antineutrino spectra in a combined analysis, we find that the best-fit value of the mass-squared difference $Δm^2_{21}$ decreases from $7.53^{+0.17}_{-0.16}\times10^{-5}\,\mathrm{eV^2}$ to $7.50^{+0.19}_{-0.18}\times10^{-5}\,\mathrm{eV^2}$, while the best-fit value of the mixing angle $\tan^2θ_{12}$ also shows a decreasing trend. This result is in better agreement with the latest JUNO measurement, suggesting that differences in the predicted reactor antineutrino spectra may be an important cause of the tension between the two experiments.
title Global Fit of KamLAND Data and the Daya Bay Antineutrino Energy Spectrum
topic High Energy Physics - Experiment
url https://arxiv.org/abs/2605.16915