Search for signatures of sterile neutrinos with Double Chooz

Abstract

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

$${5 \times 10^{-3}}\,\mathrm{eV}^2 \lesssim \varDelta m^2_{41} \lesssim {3 \times 10^{-1}}\,\mathrm{eV}^2 $$

5 ×

10

- 3

eV

2

≲ Δ

m 41 2

≲

3 ×

10

- 1

eV

2

for mixing angles down to

$$\sin ^2 2\theta _{14} \gtrsim {0.02} $$

sin 2

2

θ 14

≳

0.02

. No significant disappearance additionally to the conventional disappearance related to

$$\theta _{13} $$

θ 13

is observed and correspondingly exclusion bounds on the sterile mixing parameter

$$\theta _{14} $$

θ 14

as a function of

$$ \varDelta m^2_{41} $$

Δ

m 41 2

are obtained.