Effects of the Nuclear Correlations on the Neutrino-Oxygen Interactions

We perform a calculation of the absolute charged current neutrino- oxygen events rates relevant in the atmospheric neutrino experiments. The inclusive reaction cross-section is split into exclusive channels, which are classified according to the number of \v{C}erenkov rings they produce. The model includes the effects of residual interaction in a RPA scheme with both nucleon-hole and Delta-hole excited states and the effects of (np-nh) excitations (n=2,3). Our result is that although the flavor ratio $\mu/e$ remains almost unaffected by the nuclear effects considered here and often neglected in the Monte-Carlo simulations, the absolute events rates are subject to important modifications.