Neutral-to-charged current events ratio in atmospheric neutrinos and neutrino oscillations

The atmospheric neutrinos produce isolated neutral pions ($\pi^0$-events) mainly in the neutral current interactions. We propose to study the ratios involving $\pi^0$-events and the events induced mainly by the charged currents. This minimizes uncertainties related to the original neutrino fluxes, and in certain cases, also to the cross-sections. Experimental study of these ratios will allow one to check the oscillation solution of the atmospheric neutrino problem and to identify the channel of oscillations. Illustrative analysis of existing data is presented.