A Global Fit Determination of Effective $\Delta m_{31}^2$ from Baseline Dependence of Reactor ${\bar{\nu }}_e$ Disappearance

Abstract

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

Comments: 9 pages, 8 figures, edited for Physics Letters B