Measurement of the Muon Neutrino Charged Current interactions and the muon neutrino single pion cross section on CH using the T2K near detector

The T2K experiment is a long baseline neutrino experiment whichutilizes an almost pure muon neutrino beam. The main goal of theexperiment is the measurement of the oscillation parameters of themuon neutrinos. In order to achieve this goal, T2K requires anaccurate prediction of the interaction rates in the far detector,Super-KamiokaNDE. The near detector of T2K, ND280, measures theinteraction rates and estimates the number of events at the fardetector.The muon neutrino charged current interactions in the near detector(ND280) are used to predict the rate at the far detector(Super-KamiokaNDE). To a better constrain of the cross sectionparameters, which are dominant in the analysis together with the fluxuncertainty, we categorize the selected events in three differentsamples according to the number of pions in the final state. Thesecategories allow for a better constrain of the oscillation signalchannel (Charged Current Quasielastic) and the main oscillationbackground (Charged Current 1 Charged Pion).Current and future neutrino experiments are limited by neutrino crosssection uncertainties. The actual cross section models are in tensionwith the experimental data in some energy ranges. It is still criticalto study neutrino-nucleus cross sections on all possible interactionchannels. The muon neutrino charged current single pion production isone of the main channels in tension with the model. As a secondcontribution, we present the measurement of the Charged Current singlepositive pion production cross section using a model independentapproach exploring the full capability of the ND280 detector todetermine the kinematical distributions of the event. The improvedknowledge of the interactions, and in concrete for the single pionchannel, will allow the reduction of the the systematicaluncertainties in the oscillation analysis.