Analysis of the Results of the Neutrino-4 Experiment on the Search for the Sterile Neutrino and Comparison with Results of Other Experiments

New measurements of the flux and spectrum of reactor antineutrinos as functions of the distance from the center of the core of the SM-3 reactor (Dimitrovgrad, Russia) in the range of 6–12 m have been reported. Additional measurements have been performed. The amount of experimental data has been increased by almost a factor of 2. The model-independent analysis has been performed in order to determine the oscillation parameters $$\Delta m_{14}^2$$ and sin2 2θ14. The method of coherent addition of measurement results allows the direct demonstration of the effect of oscillations. The effect of oscillations is observed near the values $$\Delta m_{14}^2 = 7.25 \pm {0.13_{{\rm{st}}}} \pm {1.08_{{\rm{sys}}}}$$ and sin2 2θ = 0.26 ± 0.08stat ± 0.05syst. This result has been compared to the results of other experiments on the search for the sterile neutrino. The joint analysis of the Neutrino -4 experiment with the gallium and reactor anomalies gives the value sin2 2θ14 ≈ 0.19 ± 0.04 (4.6σ). The results of the Neutrino-4 experiment have been compared to the results of the NEOS, DANSS, STEREO, and PROSPECT reactor experiments; MiniBooNE and LSND accelerator experiments; and IceCube experiment. According to the Neutrino-4 experiment (under the assumption that $$m_4^2 \approx \Delta m_{14}^2$$ ), the mass of the sterile neutrino is m4 = (2.68 ± 0.13) eV. The calculations with the estimates of the mixing angles from other experiments give the values $$m_{{V_e}}^{{\rm{eff}}} = (0.58 \pm 0.09)\;{\rm{eV}}$$ , $$m_{{V_\mu}}^{{\rm{eff}}} = (0.42 \pm 0.24)\;{\rm{eV}}$$ , and $$m_{{V_\tau}}^{{\rm{eff}}} \le 0.65\;{\rm{eV}}$$ for the masses of the electron, muon, and tau neutrinos, respectively. The extended Pontecorvo—Maki—Nakagawa—Sakata matrix for the 3 + 1 model with one sterile neutrino is given.