2003 Fiscal Year Final Research Report Summary
Neutrino Physics Related to Long Baseline Experiments
| Project/Area Number |
13640295
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
YASUDA Osamu Tokyo Metropolitan Univ., Physics Dept., Assist.Prof., 理学研究科, 助手 (50183116)
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| Project Period (FY) |
2001 – 2003
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| Keywords | neutrino oscillation / flavor mixing / neutrino mass / CP violation / MSW effect / long baseline neutrino experiment / neutrino factory / sterile neutrino |
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| Research Abstract |
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.
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