1210.8141 (Shao-Feng Ge et al.)

Determination of mass hierarchy with medium baseline reactor neutrino
experiments    [PDF]

Shao-Feng Ge, Kaoru Hagiwara, Naotoshi Okamura, Yoshitaro Takaesu

We study the sensitivity of future medium baseline reactor antineutrino experiments on the neutrino mass hierarchy. By using the standard chi^2 analysis, we find that the sensitivity depends strongly on the baseline length L and the energy resolution (delta E/E)^2 = (a/sqrt{E/MeV})^2 + b^2, where a and b parameterize the statistical and systematic uncertainties, respectively. The optimal length is found to be L ~ 40-55 km, the larger resolution the shorter optimal L. The running time needed to determine the mass hierarchy depends strongly on the energy resolution. The three-sigma determination is possible after 10 years of running with a = 3% and b = 0.5%, which can be reduced to 4 years if a = 2% and b = 0.5%, for a 5 kton detector (with 12% weight fraction of free proton) placed at L ~ 50 km away from a 20 GW_{th} reactor. This type of experiment can measure the relevant mixing parameters accurately, achieving delta sin^2(2theta_{12}) ~ 4*10^{-3}, delta (m_2^2-m_1^2) ~ 0.03*10^{-5} eV^2, and delta |m_3^2 -m_1^2| ~ 0.007*10^{-3} eV^2, after 5 years.

View original: http://arxiv.org/abs/1210.8141