arXiv 1303.46672013-03-20hep-exnucl-exphysics.geo-ph

用KamLAND测量反应堆通断反中微子

Reactor On-Off Antineutrino Measurement with KamLAND

The KamLAND Collaboration

备注：: 9 pages, 8 figures. Fig.4 (b) has been replaced with the corrected version

摘要：

日本核反应堆最近长期关闭，导致Kamland的反应堆$\bar{nu}_{e}$通量大幅减少。该运行条件为反应堆$\bar{nu}_{e}$振荡分析提供了确认和约束背景的独特机会。该数据集还提高了对其他$\bar{nu}_{e}$信号的灵敏度，特别是在$β$中产生的$\bar{nu}_{e}$信号，即地球内部的$^{238}$ U和$^{232}$ Th的衰变，其能谱与反应堆$\bar{nu}_{e}$的能谱重叠。包括从加速器和短基线反应堆中微子实验$θ_{13}$的约束，结合太阳和KamLAND数据的三味分析给出了适合的值的振荡参数的$tan^{2} θ_{12} = 0.436^{+0.029}_{-0.025}$，$Δm^{2}_{21} = 7.53^{+0.18}_{-0.18} \times 10^{-5} {eV}^{2}$，和$sin^{2} θ_{13} = 0.023^{+0.002}_{-0.002}$。假设钍/铀的质量比为常数，我们从$^{238}$ U和$^{232}$ Th得到$116^{+28}_{-27}$ $\bar{nu}_{e}$事件，对应于KamLAND位置的地质$\bar{nu}_{e}$通量为$3.4^{+0.8}_{-0.8} \times 10^{6} {cm^{-2}s^{-1}}$。我们评估各种散装硅酸盐地球成分模型使用所观察到的地球$\bar{nu}_{e}$率。

英文摘要：

The recent long-term shutdown of Japanese nuclear reactors has resulted in a significantly reduced reactor $\bar{nu}_{e}$ flux at KamLAND. This running condition provides a unique opportunity to confirm and constrain backgrounds for the reactor $\bar{nu}_{e}$ oscillation analysis. The data set also has improved sensitivity for other $\bar{nu}_{e}$ signals, in particular $\bar{nu}_{e}$'s produced in $β$-decays from $^{238}$U and $^{232}$Th within the Earth's interior, whose energy spectrum overlaps with that of reactor $\bar{nu}_{e}$'s. Including constraints on $θ_{13}$ from accelerator and short-baseline reactor neutrino experiments, a combined three-flavor analysis of solar and KamLAND data gives fit values for the oscillation parameters of $tan^{2} θ_{12} = 0.436^{+0.029}_{-0.025}$, $Δm^{2}_{21} = 7.53^{+0.18}_{-0.18} \times 10^{-5} {eV}^{2}$, and $sin^{2} θ_{13} = 0.023^{+0.002}_{-0.002}$. Assuming a chondritic Th/U mass ratio, we obtain $116^{+28}_{-27}$ $\bar{nu}_{e}$ events from $^{238}$U and $^{232}$Th, corresponding to a geo $\bar{nu}_{e}$ flux of $3.4^{+0.8}_{-0.8} \times 10^{6} {cm^{-2}s^{-1}}$ at the KamLAND location. We evaluate various bulk silicate Earth composition models using the observed geo $\bar{nu}_{e}$ rate.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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英文摘要：

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