发表机构
IPHC, Université de Strasbourg, CNRS/IN2P3; University of Jyvaskyla; GSI Helmholtzzentrum für Schwerionenforschung GmbH; Institute of Physics and EC PRISMA + , Johannes Gutenberg Universität Mainz; Sun Yat-sen University; The University of Liverpool; INFN Catania and Dipartimento di Fisica e Astronomia dell Università di Catania; Joint Institute for Nuclear Research; INFN Sezione di Milano and Dipartimento di Fisica dell Università di Milano; INFN Milano Bicocca and University of Milano Bicocca（斯特拉斯堡大学; 于韦斯屈莱大学; 德国重离子研究中心; 美因茨约翰内斯·古腾堡大学; 中山大学; 利物浦大学; 意大利国家核物理研究所卡塔尼亚分部及卡塔尼亚大学; 俄罗斯联合核研究所; 意大利国家核物理研究所米兰分部及米兰大学; 意大利国家核物理研究所米拉比科卡分部及米拉比科卡大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
基于JUNO 207.2天数据，精确测量中微子振荡参数，并利用长基线实验约束，以2.1σ显著性和贝叶斯因子10.18支持正常质量顺序。
AI 中文摘要
我们报告了在江门地下中微子观测站（JUNO）对中微子振荡参数的改进测量，以及由此产生的对中微子质量顺序的指示。该分析基于207.2天的有效数据，包含在平均反应堆基线52.5公里处收集的8,294个逆β衰变候选事件。大气中微子质量劈裂Δm²₃₁达到了约1%的世界领先精度，在正常顺序下Δm²₃₁=+2.509⁺⁰·⁰²⁷₋₀·₀₂₅×10⁻³ eV²，在反转顺序下Δm²₃₁=-2.482⁺⁰·⁰²⁵₋₀·₀₂₆×10⁻³ eV²，在拟合中使用了Daya Bay约束来解析每种质量顺序假设下的正确物理最小值。我们进一步改进了太阳振荡参数的世界最精确测量，得到sin²θ₁₂=0.3036±0.0064和Δm²₂₁=(7.388±0.078)×10⁻⁵ eV²，分别对应2.1%和1.1%的相对精度。将长基线加速器中微子实验对Δm²₃₁的约束纳入我们的分析后，正常顺序优于反转顺序，在所有可能的CP破坏相位下，单侧显著性至少为2.1σ；贝叶斯分析得到的贝叶斯因子为10.18，支持正常顺序。
英文摘要
We report an improved measurement of neutrino oscillation parameters at the Jiangmen Underground Neutrino Observatory (JUNO) and the consequent indication of neutrino mass ordering. The analysis is based on 207.2 live days of data, comprising 8,294 inverse beta-decay candidates collected at an average reactor baseline of 52.5 km. A world-leading precision of approximately 1% was achieved for the atmospheric neutrino mass splitting $Δm^2_{31}$, with $Δm^2_{31}=+2.509^{+0.027}_{-0.025}\times10^{-3}\,\mathrm{eV}^2$ for normal ordering and $Δm^2_{31}=-2.482^{+0.025}_{-0.026}\times10^{-3}\,\mathrm{eV}^2$ for inverted ordering, using the Daya Bay constraint in the fit to resolve the correct physical minimum under each mass-ordering hypothesis. We further improved the world's most precise measurements of the solar oscillation parameters, obtaining $\sin^2θ_{12}=0.3036\pm0.0064$ and $Δm^2_{21}=(7.388\pm0.078)\times10^{-5}\,\mathrm{eV}^2$, corresponding to relative precisions of 2.1% and 1.1%, respectively. Incorporating constraints on $Δm^2_{31}$ from long-baseline accelerator neutrino experiments into our analysis favored normal ordering over inverted ordering, with a one-sided significance of at least $2.1σ$ across all possible CP-violating phases; a Bayesian analysis yielded a Bayes factor of 10.18 in favor of normal ordering.
Comments12 pages, 8 figures
