2025-12-12 オックスフォード大学
The 12-metre-diameter acrylic vessel surrounded by 9,000 photomultiplier tubes at the heart of the the Sudbury Neutrino Observatory and SNO+ experiments. The vessel currently holds about 800 tonnes of liquid scintillator for neutrino detection. Image credit: SNOLAB.
＜関連情報＞
- https://www.ox.ac.uk/news/2025-12-12-new-breakthrough-detecting-ghost-particles-sun
- https://journals.aps.org/prl/abstract/10.1103/1frl-95gj
太陽ニュートリノ相互作用の最初の証拠13C First Evidence of Solar Neutrino Interactions on 13C
M. Abreu, A. Allega, M. R. Anderson, S. Andringa, D. M. Asner, D. J. Auty, A. Bacon, T. Baltazar, F. Barão, et al. (SNO+ Collaboration)
Physical Review Letters Published 10 December, 2025
DOI: https://doi.org/10.1103/1frl-95gj
Abstract
The SNO+ Collaboration reports the first evidence of 8B solar neutrinos interacting on 13C nuclei. The charged current interaction proceeds through 13C+→13N+e− which is followed, with a 10 minute half life, by 13N→13C+e++. The detection strategy is based on the delayed coincidence between the electron and the positron. Evidence for the charged current signal is presented with a significance of 4.2. Using the natural abundance of 13C present in the scintillator, 5.7 metric tons of 13C over 231 days of data were used in this analysis. The 5.6+3.0−2.3 observed events in the data set are consistent with the expectation of 4.7+0.6−1.3 events. This result is the second real-time measurement of CC interactions of 8B neutrinos with nuclei and constitutes the lowest energy observation of neutrino interactions on 13C generally. This enables the first direct measurement of the CC reaction to the ground state of 13N, yielding an average cross section of (16.1+8.5−6.7(stat.)+1.6−2.7(syst.))×10−43 cm2 over the relevant 8B solar neutrino energies.
