Neutrino Physics Related to Long Baseline Experiments

我讨论了在中微子工厂测量CP破坏的可能性。我指出，如果地球密度的不确定度大于10%，或者本底/信号比大于10^-lt；-3；，则对于基线小于1000公里、Muon能量小于20GeV的信号进行优化。我证明，在长基线实验中，如果基线较短，物质效应对第二个非平凡数量级的影响可以忽略不计。利用相同的形式，我推导出了恒定密度物质和恒定磁场中任意味物质的振荡几率的解析公式。我建议用反应堆中微子测量第三混合角θ_&lt；13&gt；。我证明了反应堆中微子方法起到了对加速器实验的补充作用，将它们结合起来可以解决一些参数简并问题。我还讨论了由于多个反应堆的性质而引起的各种系统误差等因素对SIN^2 2θ_(13)的灵敏度。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，而对于任何反应堆实验，其灵敏度充其量约为0.01。我讨论了在JPARC中微子和反中微子测量之后，如何通过在(SIN^2 2θ_&lt；13&gt；，1/S^2_&lt；23&gt；)平面上的新作图来解决参数简并问题。我发现，如果JPARC或偏离轴NUMI的低能耗选项在实验中是可行的，那么它可以解决θ_&lt；23&gt；⇔π-δ和Δm^2_&lt；31&gt；⇔-Δm^2_&lt；31&gt；的歧义。我证明了测量ν_e→ν_τ也是有用的。

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.