Constraining systematic uncertainties using T2K Near Detector with X and Y FGD2 scintillator layers information in Markov chain Monte Carlo framework

T2K (Tokai to Kamioka) is a long baseline neutrino oscillation experiment in Japan. It consists of a near detector (ND280) and a far detector (FD) Super-Kamiokande to make precise measurements of neutrino oscillations parameters and ultimately to determine the presence of CP violation in the lepton sector. The Japan Proton Accelerator Research Complex (J-PARC) produces a muon (anti-)neutrino beam which is aimed towards the Far Detector 295km away. The work presented here uses data collected by ND280, which measures neutrino flux and interaction cross sections pre-oscillation, and utilises a Monte Carlo Markov chain framework to constrain the predicted event spectra for the Far Detector. The flux and interaction models used in this analysis are parameterised via prior predictions and uncertainties from theoretical calculations, external data and precise flux measurements. In this thesis, a discussion on the inclusion of new samples using X and Y scintillator layer information in FGD2 to constrain events on Carbon and Oxygen as target materials. T2K has made world-leading measurements of Oscillation parameters, with the ND280 data providing crucial measurements to reduce the uncertainty by a factor of 6 to the Far Detector prediction. This analysis utilises ND280 data from T2K Runs2-9, and flux and cross section models used in the Oscillation Analysis of 2021.