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Neutrino Physics Related to Long Baseline Experiments

与长基线实验相关的中微子物理

基本信息

批准号：
13640295
负责人：
YASUDA Osamu
金额：
$ 2.24万
依托单位：
Tokyo Metropolitan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640295/
关键词：
neutrino oscillation flavor mixing neutrino mass CP violation MSW effect long baseline neutrino experiment neutrino factory sterile neutrino スピンフレーバー共鳴原子炉ニュートリノ振動実験パラメーター縮退

项目摘要

I discussed the possibility of measurement of CP violation at a neutrino factory. I showed that the signal is optimized for the baseline less than 1000km and the muon energy less than 20GeV, if the uncertainty of the density of the Earth is more than 10% or if the background/signal ratio is more than 10^<-3>. I showed that the matter effect is negligible to the second nontrivial orders in long baseline experiments, if the baselines are short. Using the same formalism I derived the analytical formula for the oscillation probability in the matter with constant density and in a constant magnetic field for the arbitrary numbers of flavors. I proposed to measure the third mixing angle θ_<13> using reactor neutrinos. I showed that the reactor neutrino method plays a role complementary to accelerator experiments and that some of parameter degeneracy can be resolved by combining them. I also discussed the sensitivity to sin^2 2θ_<13>, taking into account various kinds of systematic errors due to the nature of multiple reactors etc. I found hat the sensitivity to sin^2 2θ_<13> is about 0.02 in the case of the Kashiwazaki plan, and can be about 0.01 for any reactor experiment at best. I discussed how parameter degeneracy can be resolved by an experiment after the JPARC measurements of neutrinos and anti-neutrinos, using the new plot in the (sin^2 2θ_<13>, 1/s^2_<23>) plane. I found that, if low energy option is experimentaly possible at JPARC or off axis NuMI, then it could resolve the ambiguities of θ_<23> ⇔ π-δ, and Δm^2_<31> ⇔ -Δm^2_<31>. I showed that measurement of ν_e → ν_τ is also useful.

我讨论了在中微子工厂测量CP破坏的可能性。我表明，如果地球密度的不确定性大于10%，或者背景/信号比大于10^<-3>，则在基线小于1000km， μ子能量小于20GeV时，信号是优化的。我表明，在长基线实验中，如果基线很短，物质效应对于第二非平凡阶是可以忽略不计的。使用相同的形式，我导出了恒定密度和恒定磁场下任意数量口味的振荡概率的解析公式。我提出用反应堆中微子测量第三个混合角θ_<13>。我证明了反应堆中微子方法对加速器实验的补充作用，并且通过结合它们可以解决一些参数简并问题。我还讨论了对sin^2 θ_<13>的灵敏度，考虑到由于多个反应堆的性质等引起的各种系统误差。我发现，在柏崎计划的情况下，对sin^2 θ_<13>的灵敏度约为0.02，而在任何反应堆实验中，灵敏度最多约为0.01。我讨论了在JPARC测量中微子和反中微子之后，如何利用（sin^2 θ_<13>, 1/s^2_<23>）平面上的新图来解决参数简并问题。我发现，如果低能量选项在JPARC或离轴NuMI实验上是可能的，那么它可以解决θ_<23>⇔π-δ和Δm^2_<31>⇔-Δm^2_<31>的模糊性。我证明了ν_e→ν_τ的测量也是有用的。