Measurement of the inclusive <em>ν_μ</em> charged current cross section on carbon in the near detector of the T2K experiment

T2K has performed the first measurement of νμ inclusive charged current interactions on carbon at neutrino energies of ∼1  GeV where the measurement is reported as a flux-averaged double differential cross section in muon momentum and angle. The flux is predicted by the beam Monte Carlo and external data, including the results from the NA61/SHINE experiment. The data used for this measurement were taken in 2010 and 2011, with a total of 10.8×1019 protons-on-target. The analysis is performed on 4485 inclusive charged current interaction candidates selected in the most upstream fine-grained scintillator detector of the near detector. The flux-averaged total cross section is ⟨σCC⟩ϕ=(6.91±0.13(stat)±0.84(syst))×10−39  cm2nucleon for a mean neutrino energy of 0.85 GeV