Observation of _µ _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 µ 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 µ e oscillation in the T2K (Tokai to

Kamioka) experiment is presented and a new constraint on dCP is obtained. This measurement and the analysis establish, at greater than 5s significance, the observation of µ e oscillation for the first time in the world. Combining

the T2K µ e oscillation measurement with the latest findings on oscillation parameters including the world average value of 13 from reactor experiments,

the constraint on the value of dCP at the 90% confidence level is obtained.

This constraint on dCP is an important step towards the discovery of CP

violation in the lepton sector.

Résumé

In this thesis the author contributes to the analysis of neutrino beam data collected between 2010 and 2013 to identify e events at the Super-Kamiokande detector. In particular, the author improves the pionnucleus interaction uncertainty, which is one of the dominant systematic error sources inT2K neutrino oscillation measurement. In the thesis, the measurement of e oscillation in the T2K (Tokai to Kamioka) experiment is presented and a new constraint on CP is obtained. This measurement and the analysis establish, at greater than 5 significance, the observation of e oscillation for the first time in the world. Combining the T2K e oscillation measurement with the latest findings on oscillation parameters including the world average value of 13 from reactor experiments, the constraint on the value of CP *at the 90% confidence level is obtained. This constraint on *CP is an important step towards the discovery of CP violation in the lepton sector.

Contenu
Introduction.- Overview of the T2K experiment.- The Fine-Grained Detector.- Pion Interaction measurement at TRIUMF M11 Beamline.- Extraction of Pion Absorption and Charge Exchange Cross Section.- Improvement of pion interaction model.- Monte Carlo Simulation for the Oscillation Analysis.- Near Detector Measurement.- Far Detector Measurement.- Oscillation Analysis and Results.- Conclusion.