<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>ψ</mml:mi></mml:math>production in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mrow><mml:mover><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>¯</mml:mi></mml:mrow></mml:mover></mml:mrow></mml:mrow><mml:mi>N</mml:mi></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>π</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:mrow><mml:mi>N</mml:mi></mml:math>interactions at 125 GeV/<i>c</i>and a determination of the gluon structure functions of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mrow><mml:mover><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>¯</mml:mi></mml:mrow></mml:mover></mml:mrow></mml:mrow></mml:math>and the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>π</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>

We have measured the cross section for production of $\ensuremath{\psi}$ and ${\ensuremath{\psi}}^{\ensuremath{'}}$ in $\overline{p}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$ interactions with Be, Cu, and W targets in experiment E537 at Fermilab. The measurements were performed at 125 GeV/c using a forward dimuon spectrometer in a closed geometry configuration. The gluon structure functions of the $\overline{p}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$ have been extracted from the measured $\frac{d\ensuremath{\sigma}}{d{x}_{F}}$ spectra of the produced $\ensuremath{\psi}'\mathrm{s}$. From the $\overline{p}\mathrm{W}$ data we obtain, for $\overline{p}$, $\mathrm{xG}(x)=(2.15\ifmmode\pm\else\textpm\fi{}0.7){[1\ensuremath{-}x]}^{(6.83\ifmmode\pm\else\textpm\fi{}0.5)}[1+(5.85\ifmmode\pm\else\textpm\fi{}0.95)x]$. In the ${\ensuremath{\pi}}^{\ensuremath{-}}$ case, we obtain, from the W and the Be data separately, $\mathrm{xG}(x)=(1.49\ifmmode\pm\else\textpm\fi{}0.03){[1\ensuremath{-}x]}^{(1.98\ifmmode\pm\else\textpm\fi{}0.06)}$ (for ${\ensuremath{\pi}}^{\ensuremath{-}}\mathrm{W}$), $\mathrm{xG}(x)=(1.10\ifmmode\pm\else\textpm\fi{}0.10){[1\ensuremath{-}x]}^{(1.20\ifmmode\pm\else\textpm\fi{}0.20)}$ (for ${\ensuremath{\pi}}^{\ensuremath{-}}\mathrm{Be}$).