Study of quasielastic scattering using charged-current nu(mu)-iron Interactions In the MINOS near detector

Abstract

Kinematic distributions from an inclusive sample of 1.41 x 10(6) charged-current nu(mu) interactions on iron, obtained using the MINOS near detector exposed to a wide-band beam with peak flux at 3 GeV, are compared to a conventional treatment of neutrino scattering within a Fermi gas nucleus. Results are used to guide the selection of a subsample enriched in quasielastic nu Fe-mu interactions, containing an estimated 123,000 quasielastic events of incident energies 1 < E-nu < 8 GeV, with < E-nu > = 2.79 GeV. Four additional subsamples representing topological and kinematic sideband regions to quasielastic scattering are also selected for the purpose of evaluating backgrounds. Comparisons using subsample distributions in four-momentum transfer Q(2) show the Monte Carlo model to be inadequate at low Q(2). Its shortcomings are remedied via inclusion of a Q(2)-dependent suppression function for baryon resonance production, developed from the data. A chi-square fit of the resulting Monte Carlo simulation to the shape of the Q(2) distribution for the quasielastic-enriched sample is carried out with the axial-vector mass M-A of the dipole axial-vector form factor of the neutron as a free parameter. The effective M-A which best describes the data is 1.23(-0.09)(+0.13)(fit)(-0.15)(+0.12)(syst) GeV.

Kinematic distributions from an inclusive sample of 1.41 x 10(6) charged-current nu(mu) interactions on iron, obtained using the MINOS near detector exposed to a wide-band beam with peak flux at 3 GeV, are compared to a conventional treatment of neutrino scattering within a Fermi gas nucleus. Results are used to guide the selection of a subsample enriched in quasielastic nu Fe-mu interactions, containing an estimated 123,000 quasielastic events of incident energies 1 < E-nu < 8 GeV, with < E-nu > = 2.79 GeV. Four additional subsamples representing topological and kinematic sideband regions to quasielastic scattering are also selected for the purpose of evaluating backgrounds. Comparisons using subsample distributions in four-momentum transfer Q(2) show the Monte Carlo model to be inadequate at low Q(2). Its shortcomings are remedied via inclusion of a Q(2)-dependent suppression function for baryon resonance production, developed from the data. A chi-square fit of the resulting Monte Carlo simulation to the shape of the Q(2) distribution for the quasielastic-enriched sample is carried out with the axial-vector mass M-A of the dipole axial-vector form factor of the neutron as a free parameter. The effective M-A which best describes the data is 1.23(-0.09)(+0.13)(fit)(-0.15)(+0.12)(syst) GeV.