Improved measurement of electron antineutrino disappearance at Daya Bay

An F P^*; An Q; Bai J Z; Balantekin A B; Band H R; Beriguete W; Bishai M; Blyth S; Brown R L; Cao G F; Cao J; Carr R; Chan W T; 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 X S; Chen Y; Chen Y X; Cherwinka J J; Chu M C; Cummings J P; Deng Z Y; Ding Y Y; Diwan M V; Draeger E; Du X F; Dwyer D; Edwards W R; Ely S R; Fang S D; Fu J Y; Fu Z W

SCI

东莞理工学院; 北京师范大学; 成都理工大学; 华北电力大学; 南京大学; 南开大学; 清华大学; 山东大学; 上海交通大学; 西安交通大学; 中国原子能科学研究院; 中山大学; 香港中文大学; 香港大学; 中国科学院

摘要

We report an improved measurement of the neutrino mixing angle theta(13) from the Daya Bay Reactor Neutrino Experiment. We exclude a zero value for sin(2)2 theta(13) with a significance of 7.7 standard deviations. Electron antineutrinos from six reactors of 2.9 GW(th) were detected in six antineutrino detectors deployed in two near (flux-weighted baselines of 470 m and 576 m) and one far (1648 m) underground experimental halls. Using 139 days of data, 28909 (205308) electron antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to the expected number of antineutrinos assuming no oscillations at the far hall is 0.944 +/- 0.007(stat.)+/- 0.003(syst.). An analysis of the relative rates in six detectors finds sin(2)2 theta(13)= 0.089 +/- 0.010(stat.)+/- 0.005(syst.) in a three-neutrino framework.

关键词

neutrino oscillation neutrino mixing reactor Daya Bay