A Global Fit Determination of Effective $Δm_{31}^2$ from Baseline Dependence of Reactor $\barν_e$ Disappearance

Abstract

Recently, three reactor neutrino experiments, Daya Bay, Double Chooz and RENO have directly measured the neutrino mixing angle $θ_{13}$. In this paper, another important oscillation parameter, effective $Δm_{31}^2$ (= $Δ\tilde{m}_{31}^2$) is measured using baseline dependence of the reactor neutrino disappearance. A global fit is applied to publicly available data and $Δ\tilde{m}_{31}^2 = 2.95^{+0.42}_{-0.61} \times 10^{-3}$ eV$^2$, $\sin^22θ_{13} = 0.099^{+0.016}_{-0.012}$ are obtained by setting both parameters free. This result is complementary to $Δtilde{m}_{31}^2$ to be measured by spectrum shape analysis. The measured $Δ\tilde{m}_{31}^2$ is consistent with $Δ\tilde{m}_{32}^2$ measured by $ν_μ$ disappearance in MINOS, T2K and atmospheric neutrino experiments within errors. The minimum $χ^2$ is small, which means the results from the three reactor neutrino experiments are consistent with each other.