A study of the axial-vector form factor and second-class currents in antineutrino quasielastic scattering

The antineutrino quasielastic reaction ν μm p →μ + n has been studied in the Q 2 range up to 1.0 (GeV/ c ) 2 at the Brookhaven AGS. The value of the axial vector mass M A in the dipole parametrization of the from factor was determined from the shape of the Q 2 distribution to be 1.09±0.03±0.02 GeV/ c 2 . A search for second-class currents was also conducted. No significant effect was found.