Measurement of the inclusive νμ charged current cross section on carbon in the near detector of the T2K experiment

T2K has performed the first measurement of ν_μ 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 $⟨{{σ}}CC{⟩}_{{φ}}=(6.91±{}0.13(stat)±{}0.84(syst))×{}{10}^{{-}39} {{cm}²}{nucleon}$ for a mean neutrino energy of 0.85 GeV.