Observation of nu_mu-->nu_e Oscillation in the T2K Experiment

In this thesis the author contributes to the analysis of neutrino beam data collected between 2010
and 2013 to identify ν_μ→ν_e events at the Super-Kamiokande detector. In particular,
the author improves the pion–nucleus interaction uncertainty, which is one of the dominant systematic error sources in T2K neutrino oscillation measurement.
In the thesis, the measurement of ν_μ→ν_e oscillation in the T2K (Tokai to
Kamioka) experiment is presented and a new constraint on δ_CP is obtained. This measurement and the analysis establish, at greater than 5σ significance, the observation of ν_μ→ν_e oscillation for the first time in the world. Combining the T2K ν_μ→ν_e oscillation measurement with the latest findings on oscillation parameters including the world average value of θ_13 from reactor experiments,
the constraint on the value of δ_CP at the 90% confidence level is obtained.
This constraint on δ_CP is an important step towards the discovery of CP
violation in the lepton sector.