Feynman-x and transverse momentum dependence of D± and D0,bar D0 production in 250 GeV π--nucleon interactions

We measure the differential cross section with respect to Feynman-x (xF) and transverse momentum (PT) for charm meson production using targets of Be, Al, Cu and W. In the range 0.1≤xF≤0.7, dσ/dxF is well fit by the form (1-xF)n with n=3.9±0.2. The difference between n values for D- and D+ is 1.1±0.4. However, we find an asymmetry of 0.18±0.04 favoring the production of D- compared to D+. In the lower PT range, ≤2 GeV, dσ/dP2T is well fit by the form exp(-bxP2T) with b=1.03±0.04 GeV-2, while in the higher PT range, 0.8 to 3.6 GeV, it is well fit by the form exp(-b'xPT) with b'=2.76±0.06 GeV-1. The shape of the differential cross section has no significant dependence on atomic mass of the target material