Study of the numu interactions via charged current in the t2k near detector

Résumé

T2K is a long baseline experiment located in Japan, which aims to measure neutrino oscillation. An accelerator is used to produce neutrino, which are detected in a far detector (Super-Kamiokande) and a near detector complex (both INGRID and ND280). It was design to be sensitive to the $\nu_\mu \rightarrow \nu_\mu$ and $\nu_\mu \rightarrow \nu_e$ channels, which mainly depends on $\theta_{23}$ and $\theta_{13}$ parameters from the PMNS matrix respectively. Currently, T2K provides competitive results for all those factors and the first hint for the violation of CP symmetry in the leptonic sector has just been released. ND280 plays a fundamental role in the oscillation analysis. It is used to constrain the systematic uncertainties associated to both the flux and cross section by measuring the rate of $\nu_\mu$ and $\nu_e$ interactions. Fine grained detectors (FGDs) are narrow scintillators layers (made of plastic) designed to have very good vertexing capability, which makes then a perfect target. They are surrounded by Time Projection Chambers (TPCs), whose performance identifying particles is outstanding. Besides, Electromagnetic Calorimeters (ECals) cover both FGDs and TPCs and they have been designed to tag MIP tracks. Everything is embedded in a magnet, which allows us to measure both momentum and charge of the tracks with a high precision. The analysis described in this thesis study $\nu_\mu$-nucleus interactions via Charged Current (CC) happening in the FGD. From this interaction a muon is produced plus hadrons, which are generated within the nuclear media. This analysis aims to reconstruct the outgoing muon, increasing the angular acceptance with respect previous analysis. The goal is to provide a sample of $\nu_\mu$ CC interaction that mimic the features of such interactions when they are detected in the far detector. Consequently, the extrapolation of systematic uncertainties from near to far detector becomes more robust. Such sample provides the perfect opportunity to report a double differential cross section for $\nu_\mu$ CC interaction on plastic as function of the muon momentum and angle.