Background study on ν_e appearance from a ν_μ beam in very long baseline neutrino oscillation experiments with a large water Cherenkov detector

There is a growing interest in very long baseline neutrino oscillation experimentation using an accelerator produced neutrino beam as a machinery to probe the last three unmeasured neutrino oscillation parameters: the mixing angle θ₁₃, the possible CP violating phase δ_CP and the mass hierarchy, namely, the sign of Δm322. Water Cherenkov detectors such as IMB, Kamiokande and Super-Kamiokande have shown to be very successful at detecting neutrino interactions. Scaling up this technology may continue to provide the required performance for the next generation of experiments. This report presents the latest effort to demonstrate that a next generation (>100kton) water Cherenkov detector can be used effectively for the rather difficult task of detecting ν_es from the neutrino oscillation ν_μ→ν_e despite the large expected potential background resulting from π0s produced via neutral current interactions.