Measurement of geo-neutrinos from 1353 days of Borexino
Measurement of geo-neutrinos from 1353 days of Borexino
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DOI：
10.1016/j.physletb.2013.04.030
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发表时间：
2013-05-24
影响因子：
4.4
通讯作者：
Zuzels, G.
中科院分区：
文献类型：
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作者：
Bellini, G.;Benziger, J.;Zuzels, G.
我们展示了利用位于意大利格兰萨索国家实验室的博雷西诺探测器在1353天的数据中所获得的地球中微子信号的测量结果。在进行了所有筛选切割以及扣除背景之后，有效曝光量为（3.69±0.16）×10³¹质子×年，假设球粒陨石质量钍/铀比固定为3.9，我们探测到了（14.3±4.4）个地球中微子事件。这对应于一个地球中微子信号S - geo =（38.8±12.0）太纳单位（TNU），而地球中微子测量值为零的概率仅为6×10⁻⁶。在拟合中将铀和钍作为自由参数时，相对信号分别为S - Th =（10.6±12.7）TNU和S - U =（26.5±19.5）TNU。仅博雷西诺的数据与地幔地球中微子信号（15.4±12.3）TNU相符，而与神冈探测器数据的联合分析能够提取出地幔信号为（14.1±8.1）TNU。我们对31.2⁻⁶.¹⁺⁷.⁰个反应堆反中微子事件的测量结果与存在中微子振荡时的预期相符。（c）2013爱思唯尔有限公司。保留所有权利。
We present a measurement of the geo-neutrino signal obtained from 1353 days of data with the Borexino detector at Laboratori Nazionali del Gran Sasso in Italy. With a fiducial exposure of (3.69 +/- 0.16) x 10(31) proton x year after all selection cuts and background subtraction, we detected (14.3 +/- 4.4) geo-neutrino events assuming a fixed chondritic mass Th/U ratio of 3.9. This corresponds to a geo-neutrino signal S-geo = (38.8 +/- 12.0) TNU with just a 6 x 10(-6) probability for a null geo-neutrino measurement. With U and Th left as free parameters in the fit, the relative signals are S-Th = (10.6 +/- 12.7) TNU and S-U = (26.5 +/- 19.5) TNU. Borexino data alone are compatible with a mantle geo-neutrino signal of (15.4 +/- 12.3) TNU, while a combined analysis with the KamLAND data allows to extract a mantle signal of (14.1 +/-. 8.1) TNU. Our measurement of 31.2(-6.1)(+7.0) reactor anti-neutrino events is in agreement with expectations in the presence of neutrino oscillations. (c) 2013 Elsevier B.V. All rights reserved.