High-energy quasielastic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>ν</mml:mi></mml:mrow><mml:mrow><mml:mi>μ</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mi>n</mml:mi><mml:mo>→</mml:mo><mml:mrow><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:mrow><mml:mi>p</mml:mi></mml:math>scattering in deuterium

We have studied the quasielastic reaction ${\ensuremath{\nu}}_{\ensuremath{\mu}}n\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}p$ in an exposure of the Fermilab deuterium-filled 15-foot bubble chamber to a high-energy wide-band neutrino beam. From an analysis of the ${Q}^{2}$ distribution based on the standard $V\ensuremath{-}A$ theory, the axial-vector mass in a dipole parametrization of the axial-vector form factor is determined to be ${M}_{A}={1.05}_{\ensuremath{-}0.16}^{+0.12}$ GeV, consistent with the values previously reported from low-energy experiments.