The earth matter effects in neutrino oscillation experiments from Tokai to Kamioka and Korea
The earth matter effects in neutrino oscillation experiments from Tokai to Kamioka and Korea
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从东海到神冈和韩国的中微子振荡实验中的地球物质效应
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Ken
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文献类型：
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作者：
K. Hagiwara;N. Okamura;Ken
我们研究了东海-神冈-韩国实验（T2 KK）中的地球物质效应，T2 KK是东海的J-PARC和神冈的Super-Kamiokande（SK）之间的T2 K（东海-神冈）中微子振荡实验的扩展，其中一个额外的探测器被放置在韩国沿着相同的中微子束线。利用最近的地球物理测量，我们研究了地球物质对神冈和韩国的振荡概率的影响，发现东海到神冈基线的平均物质密度沿着为2.6 g/cm 3，东海到韩国基线的平均物质密度为2.85，2.98和3.05 g/cm 3，基线长度为L- = 1000，1100和1200 km，分别平均密度的不确定度约为6%，这是由精确测量的声速与物质密度之间的相关性的不确定度决定的.利用阶跃函数近似和傅里叶分析研究了物质密度沿着基线分布的影响.我们发现，平均物质密度主要决定νμ → νe振荡概率，第一傅立叶模的真实的部分的贡献很小但不可忽略。我们还发现，将物质密度误差从6%降低到3%，由于测量受到统计数据的限制，在本报告中考虑了在神冈的SK和韩国的100 kt探测器的T2 KK最小方案。通过将总束时间分成中微子和反中微子运行，显著改善，因为物质效应项对具有相反符号的振荡幅度有贡献。
We study the earth matter effects in the Tokai-to-Kamioka-and-Korea experiment (T2KK), which is a proposed extension of the T2K (Tokai-to-Kamioka) neutrino oscillation experiment between J-PARC at Tokai and Super-Kamiokande (SK) in Kamioka, where an additional detector is placed in Korea along the same neutrino beam line. By using recent geophysical measurements, we examine the earth matter effects on the oscillation probabilities at Kamioka and Korea.The average matter density along the Tokai-to-Kamioka baseline is found to be 2.6 g/cm3, and that for the Tokai-to-Korea baseline is 2.85, 2.98, and 3.05 g/cm3 for the baseline length of L- = 1000, 1100, and 1200 km, respectively. The uncertainty of the average density is about 6%, which is determined by the uncertainty in the correlation between the accurately measured sound velocity and the matter density.The effect of the matter density distribution along the baseline is studied by using the step function approximation and the Fourier analysis.We find that the νμ → νe oscillation probability is dictated mainly by the average matter density, with small but non-negligible contribution from the real part of the first Fourier mode.We also find that the sensitivity of the T2KK experiment on the neutrino mass hierarchy does not improve significantly by reducing the matter density error from 6% to 3%, since the measurement is limited by statistics for the minimum scenario of T2KK with SK at Kamioka and a 100 kt detector in Korea considered in this report.The sensitivity of the T2KK experiment on the neutrino mass hierarchy improves significantly by splitting the total beam time into neutrino and anti-neutrino runs, because the matter effect term contributes to the oscillation amplitudes with the opposite sign.