The DANSS Experiment: Recent Results and Perspective

Abstract

The DANSS experiment is a scintillation spectrometer of reactor antineutrinos placed at the Unit 4 reactor of the Kalinin Nuclear Power Plant about 300 km northwest of Moscow. The main fundamental aim of the experiment is search for sterile neutrinos. The experiment was commissioned in April 2016 and regular data taking has been carried out since October 2016. 7.7 million of inverse beta-decay events have been collected by March 2023. A vast exclusion area of the sterile neutrino parameters was set. In the region of the best sensitivity the limit reached \({\text{sin}}2{{\theta }^{2}} = 5 \times {{10}^{{ - 3}}}\). The reactor power has been monitored for 6.5 years. The dispersion that is not related to single measurement statistics is below 0.5%, which gives an upper estimate of the precision of the standard NPP power measurements at the level of at least 0.5%. New scintillator detectors designed to upgrade the DANSS facility were tested at an accelerator beam. Light yield better than 140 ph.e./MeV was obtained. This paper describes the results obtained during the last year and the facility upgrade plans.