Regresar

Determining neutrino mass hierarchy by precision measurements in electron and muon neutrino disappearance experiments

Abstract:

Recently a new method for determining the neutrino mass hierarchy by comparing the effective values of the atmospheric Δm2 measured in the electron neutrino disappearance channel, Δm2(ee), with the one measured in the muon neutrino disappearance channel, Δm2(μμ), was proposed. If Δm2(ee) is larger (smaller) than Δm2(μμ) the hierarchy is of the normal (inverted) type. We reexamine this proposition in the light of two very high precision measurements: Δm2(μμ) that may be accomplished by the phase II of the Tokai-to-Kamioka (T2K) experiment, for example, and Δm2(ee) that can be envisaged using the novel Mössbauer enhanced resonant ν̄e absorption technique. Under optimistic assumptions for the systematic uncertainties of both measurements, we estimate the parameter region of (θ13, δ) in which the mass hierarchy can be determined. If θ13 is relatively large, sin 22θ13 0.05, and both of Δm2(ee) and Δm2(μμ) can be measured with the precision of ∼0.5% it is possible to determine the neutrino mass hierarchy at >95% CL for 0.3π δ 1.7π for the current best fit values of all the other oscillation parameters. © 2006 The American Physical Society.