First observation of electron antineutrinos from nuclear reactors at Super-Kamiokande

@misc{abe2026first,
  title = {{First observation of electron antineutrinos from nuclear reactors at Super-Kamiokande}},
  author = {K Abe and Y Asaoka and M Harada and Y Hayato and K Hiraide and T.H Hung and K Ieki and M Ikeda and J Kameda and Y Kataoka and S Mine and M Miura and S Moriyama and K Nakagiri and M Nakahata and S Nakayama and Y Noguchi and G Pronost and K Sato and H Sekiya and R Shinoda and M Shiozawa and Y Suzuki and A Takeda and Y Takemoto and H Tanaka and S Chen and Y Itow and T Kajita and R Nishijima and K Okumura and T Tashiro and T Tomiya and X Wang and F.J. de Garay Arcones and P Fernandez and L Labarga and D Samudio and C Yanagisawa and B Jargowsky and E Kearns and J Mirabito and L Wan and T Wester and B.W Pointon and J Bian and B Cortez and N.J Griskevich and Y Jiang and M.B Smy and H.W Sobel and V Takhistov and J Hill and B.D Xu and D Jung and D.H Moon and R.G Park and B.S Yang and K Scholberg and C.W Walter},
  howpublished = {HAL},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.03143},
  eprint = {2610.03143},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-05829681v1},
}

TY  - UNPB
TI  - First observation of electron antineutrinos from nuclear reactors at Super-Kamiokande
AU  - K Abe
AU  - Y Asaoka
AU  - M Harada
AU  - Y Hayato
AU  - K Hiraide
AU  - T.H Hung
AU  - K Ieki
AU  - M Ikeda
AU  - J Kameda
AU  - Y Kataoka
AU  - S Mine
AU  - M Miura
AU  - S Moriyama
AU  - K Nakagiri
AU  - M Nakahata
AU  - S Nakayama
AU  - Y Noguchi
AU  - G Pronost
AU  - K Sato
AU  - H Sekiya
AU  - R Shinoda
AU  - M Shiozawa
AU  - Y Suzuki
AU  - A Takeda
AU  - Y Takemoto
AU  - H Tanaka
AU  - S Chen
AU  - Y Itow
AU  - T Kajita
AU  - R Nishijima
AU  - K Okumura
AU  - T Tashiro
AU  - T Tomiya
AU  - X Wang
AU  - F.J. de Garay Arcones
AU  - P Fernandez
AU  - L Labarga
AU  - D Samudio
AU  - C Yanagisawa
AU  - B Jargowsky
AU  - E Kearns
AU  - J Mirabito
AU  - L Wan
AU  - T Wester
AU  - B.W Pointon
AU  - J Bian
AU  - B Cortez
AU  - N.J Griskevich
AU  - Y Jiang
AU  - M.B Smy
AU  - H.W Sobel
AU  - V Takhistov
AU  - J Hill
AU  - B.D Xu
AU  - D Jung
AU  - D.H Moon
AU  - R.G Park
AU  - B.S Yang
AU  - K Scholberg
AU  - C.W Walter
PY  - 2026
DA  - 2026/10/02
PB  - HAL
DO  - 10.48550/arxiv.2610.03143
UR  - https://hal.science/hal-05829681v1
AB  - In 2020, Super-Kamiokande entered the SK-Gd phase, improving its sensitivity to low-energy electron antineutrinos through the detection of neutrons captured on gadolinium dissolved in the detector water. An analysis of reactor electron antineutrino data has been carried out using data from SK-Gd, with a total exposure of 411.52 live days. The observed prompt energy spectra and monthly event rates are consistent with the oscillated reactor antineutrino prediction after accounting for accidental, geoneutrino, and spallation backgrounds. The no-reactor hypothesis is disfavored with a reactor-antineutrino signal significance of approximately 6σ. The oscillation parameters are measured to be sin^2θ_12 = 0.500±0.155 and Δm^2_21 = (9.08_−0.54^+0.55) × 10^−5 eV^2. A comparison with Super-Kamiokande solar neutrino measurements shows a statistical compatibility between the two datasets at the 1.9σ level. A combined solar and reactor fit in Super-Kamiokande yields best-fit values of sin^2θ_12 = 0.332_−0.026^+0.028 and Δm^2_21 = (8.94_−0.47^+0.46) × 10^−5 eV^2.
ER  -