Search for signatures of sterile neutrinos with Double Chooz

Abstract

We present a search for signatures of neutrino mixing of electron anti-neutrinos with additional hypothetical sterile neutrino flavors using the Double Chooz experiment. The search is based on data from 5 years of operation of Double Chooz, including 2 years in the two-detector configuration. The analysis is based on a profile likelihood, i.e.\ comparing the data to the model prediction of disappearance in a data-to-data comparison of the two respective detectors. The analysis is optimized for a model of three active and one sterile neutrino. It is sensitive in the typical mass range $5 \cdot 10^{-3}$ eV$^2 \lesssim \Delta m^2_{41} \lesssim 3\cdot 10^{-1}$ eV$^2$ for mixing angles down to $\sin^2 2\theta_{14} \gtrsim 0.02$. No significant disappearance additionally to the conventional disappearance related to $\theta_{13}$ is observed and correspondingly exclusion bounds on the sterile mixing parameter $\theta_{14}$ as function of $\Delta m^2_{41}$ are obtained.Comment: accepted for publication by EPJ