Measurement of muon-antineutrino charged current cross section with single pion production in the near detector of T2K experiment

Cross section measurement is a basic tool to examine agreement between theoretical models and experimental data. The fundamental struggle is to separate signal sample from background events. Decent measurement requires nontrivial methods in order to minimize dependency on the default model and include characteristics of the detector. This will be illustrated on the example of muon-antineutrino CC interaction on carbon with single pion production in ND280 detector of the T2K experiment.