Measurement of the $ u_mu$ CCQE cross section on carbon with the ND280 detector at T2K

The Charged-Current Quasi-Elastic (CCQE) interaction, $ u_{l} + n rightarrow l^{-} + p$, is the dominant CC process at $E_ u sim 1$ GeV and contributes to the signal in accelerator-based long-baseline neutrino oscillation experiments operating at intermediate neutrino energies. This paper reports a measurement by the T2K experiment of the $ u_{mu}$ CCQE cross section on a carbon target with the off-axis detector based on the observed distribution of muon momentum ($p_mu$) and angle with respect to the incident neutrino beam ($theta_mu$). The flux-integrated CCQE cross section was measured to be $(0.83 pm 0.12) times 10^{-38}textrm{ cm}^{2}$ in good agreement with NEUT MC value of ${0.88 times 10^{-38}} textrm{ cm}^{2}$. The energy dependence of the CCQE cross section is also reported. The axial mass, $M_A^{QE}$, of the dipole axial form factor was extracted assuming the Smith-Moniz CCQE model with a relativistic Fermi gas nuclear model. Using the absolute (shape-only) $p_{mu}costheta_mu$ distribution, the effective $M_A^{QE}$ parameter was measured to be ${1.26^{+0.21}_{-0.18} textrm{ GeV}/c^{2}}$ (${1.43^{+0.28}_{-0.22} textrm{ GeV}/c^{2}}$).