Beyond Tree Level with Solar Neutrinos: Towards Measuring the Flavor Composition and CP Violation

Abstract

After being produced as electron neutrinos ($ν_e$), solar neutrinos partially change their flavor to $ν_μ$ and $ν_τ$ en route to Earth. Although the flavor ratio of the $ν_e$ flux to the total flux has been well measured, the $ν_μ:ν_τ$ composition has not yet been experimentally probed. In this work we investigate the potential of the next-generation experiments for measuring the $ν_μ:ν_τ$ flavor ratio by utilizing flavor-dependent radiative corrections in the cross sections for $ν_μ$ and $ν_τ$ scattering. Since the transition probabilities of $ν_e$ to $ν_μ$ and $ν_τ$ depend on the leptonic CP phase, we also investigate the sensitivity to the CP phase and show that a statistical significance of $\sim1 σ$ could be reached through precision measurements of solar neutrino spectra.