Matter Effects in Atmospheric Neutrino Oscillations and Radon Anomalies

Anomalies in radon activity have been discovered and debated by several organizations worldwide during radon monitoring. Based on the theory of neutrino oscillations and the latest results of the study of neutrino oscillation-induced radioactive decay, the material effects of high-energy atmospheric neutrinos oscillating in the atmosphere and their impact on the decay rate of radon have been analyzed. The results show that there is a possibility of Mikheyev-Smirnov-Wolfenstein (MSW) resonance with atmospheric materials when high-energy atmospheric neutrinos propagate oscillations in the atmosphere. This resonance has an excitation effect on radioactive radon and can increase the decay probability of radon. Simultaneously, we demonstrate that the amplitude of radon radioactivity fluctuations is positively correlated with the atmospheric neutrino flux and the intensity (or amplitude) of the MSW resonance. The atmospheric neutrino flux participating in MSW resonance and its oscillation intensity (or amplitude) are primarily influenced by two factors: (1) Air density. When air density increases due to factors like humidity rise or temperature decrease, the atmospheric neutrino flux participating in MSW resonance and the oscillation amplitude both increase (strengthening the signal). (2) Variations in cosmic ray intensity, solar activity, and atmospheric thickness fluctuations can alter the atmospheric neutrino flux, causing the MSW resonance to exhibit oscillation periods similar to those of cosmic ray intensity, solar activity, and lunar tides. Consequently, fluctuations in radon radioactivity correlate with atmospheric temperature, humidity, and solar activity.