Impact of nuclear effects on the extraction of neutrino oscillation parameters

We study the possible impact of nuclear effects and final state interactions on the determination of the oscillation parameters due to mis-reconstruction of non-quasi-elastic events as quasi-elastic events at low energies. We analyze a $\nu_\mu$ disappearance experiment using a water \v{C}erenkov detector. We find that, if completely ignored in the fit, nuclear effects can induce a significant bias in the determination of atmospheric oscillation parameters, particularly for the atmospheric mixing angle. Even after inclusion of a near detector a bias in the determination of the atmospheric mixing angle comparable to the statistical error remains.