Estimation of the DANSS Experiment Sensitivity to Neutrino Oscillations

Abstract

DANSS is a highly segmented scintillator detector with a sensitive volume of 1 m3. The detector is located at the Kalinin Nuclear Power Plant under the reactor core on a moving platform. The distance from the detector center to the reactor center is varied from 10.7 to 12.7 m. The inverse beta decay reaction is used to detect antineutrino. DANSS detects about 5000 events per day with the background level of about two percent. Sterile neutrinos are searched for within the model of three active and one sterile neutrinos. The exclusion area in the space of parameters $$\Delta m_{{14}}^{2},{{\sin}^{2}}2{{\theta }_{{14}}}$$ is based only on the ratio of positron energy spectra recorded at different distances from the detector to the reactor core. Therefore, the results are independent of the absolute detector efficiency and predicted antineutrino fluxes. The experiment sensitivity is determined using the Gaussian CLs method taking into account the systematic errors. The experimentally obtained exclusion area covers a wide range of values and is in reasonable agreement with the sensitivity. The sensitivity for the upgraded detector is estimated.