Feynman-x and transverse-momentum dependence of ${\mathit{D}}^{\pm }$ and ${\mathit{D}}^0$, D${\mathrm{¯}}^0$ production in 250 GeV ${\mathrm{\pi }}^{\mathrm{-}}$-nucleon interactions

We measure the differential cross section with respect to Feynman-x (${\mathit{x}}_{\mathit{F}}$) and transverse momentum (${\mathit{P}}_{\mathit{T}}$) for charm meson production using targets of Be, Al, Cu, and W. In the range 0.1<${\mathit{x}}_{\mathit{F}}$<0.7, dσ/${\mathit{dx}}_{\mathit{F}}$ is well fit by the form (1-${\mathit{x}}_{\mathit{F}}$ ${)}^{\mathit{n}}$ with n=3.9±0.3. The difference between n values for ${\mathit{D}}^{\mathrm{-}}$ and ${\mathit{D}}^{+}$ is 1.1±0.7. However, we find an asymmetry of 0.18±0.06 favoring the production of ${\mathit{D}}^{\mathrm{-}}$ compared to ${\mathit{D}}^{+}$. In the lower ${\mathit{P}}_{\mathit{T}}$ range, <2 GeV, dσ/${\mathit{dP}}_{\mathit{T}}^2$ is well fit by the form exp(-b×${\mathit{P}}_{\mathit{T}}^2$) with b=1.03±0.06 ${\mathrm{GeV}}^{\mathrm{-}2}$, while in the higher ${\mathit{P}}_{\mathit{T}}$ range, 0.8 to 3.6 GeV, it is well fit by the form exp(-b’×${\mathit{P}}_{\mathit{T}}$) with b’=2.76±0.08 ${\mathrm{GeV}}^{\mathrm{-}1}$. The shape of the differential cross section has no significant dependence on atomic mass of the target material.