Measurement of the $\hat{I}{½}_{\hat{I}}¼$ CCQE cross section on carbon with the ND280 detector at T2K

Abstract

The Charged-Current Quasi-Elastic (CCQE) interaction, $\hat{I}{½}_l+n\to l^{-}+p$, is the dominant CC process at $E_{\hat{I}}½\sim 1$ 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 $\hat{I}{½}_{\hat{I}}¼$ CCQE cross section on a carbon target with the off-axis detector based on the observed distribution of muon momentum ($p_{\hat{I}}¼$) and angle with respect to the incident neutrino beam ($\hat{I}{¸}_{\hat{I}}¼$). The flux-integrated CCQE cross section was measured to be $(0.83\pm 0.12)\times 10^{-38}{\text{ cm}}^2$ in good agreement with NEUT MC value of $0.88\times 10^{-38}{\text{ cm}}^2$. 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) $p_{\hat{I}}¼cos\hat{I}{¸}_{\hat{I}}¼$ distribution, the effective $M_A^{QE}$ parameter was measured to be $1.26_{-0.18}^{+0.21}\text{ GeV}/c^2$ ($1.43_{-0.22}^{+0.28}\text{ GeV}/c^2$).