Experimental indications of the 3+1 neutrino model with one sterile neutrino

Abstract

The possibility of the validation of the 3+1 neutrino model is considered in the context of the new result of the Neutrino-4 experiment, the direct observation of the oscillation effect at parameter region $\Delta m_{14}^2=(7.3 \pm 0.13_{stat} \pm 1.16_{syst})\text{eV}^2$ and $\sin^2(2\theta_{14}) = 0.36 \pm 0.12_{stat} (2.9\sigma)$, also using LSND anomaly, MiniBooNE anomaly, reactor antineutrino anomaly, and gallium anomaly observed in experiments with radioactive sources GALLEX/GNO and SAGE. We analyze agreement of the neutrino parameter values obtained in the Neutrino-4 experiment with the results of other reactor type experiments NEOS, DANSS, STEREO, PROSPECT, the experiments at accelerators MiniBooNE, LSND, and the IceCube experiment. We present the analysis of the 3+1 neutrino model which demonstrates the agreement among the experiments within current experimental accuracy. Also, current accuracy allows us to make estimations of the effective masses of the neutrinos. The mass of the sterile neutrino obtained in the Neutrino-4 experiment (in assumption $m_2^2 \approx \Delta m_{14}^2$) is $m_4 = (2.70\pm0.22)\text{eV}$. Using the estimations of the mixing angles we calculated the values of the electron, muon and tau neutrinos: $m_{4\nu_e}^{\text{eff}}=(0.82\pm0.18)\text{eV}, m_{4\nu_{\mu}}^{\text{eff}}=(0.41\pm0.26)\text{eV}, m_{4\nu_{\tau}}^{\text{eff}}\leq 0.60\text{eV}$. These results are compared with the values obtained in the experiments in the direct measurement of the neutrino mass KATRIN and GERDA. The Pontecorvo-Maki-Nakagawa-Sakata matrix with four states and the mixing scheme of the flavor neutrinos with the sterile state are presented.