Feynman- x and transverse-momentum dependence of D sup + and D sup 0 , D sup 0 production in 250 GeV. pi. sup minus -nucleon interactions

We measure the differential cross section with respect to Feynman-{ital x} ({ital x}{sub {ital F}}) and transverse momentum ({ital P}{sub {ital T}}) for charm meson production using targets of Be, Al, Cu, and W. In the range 0.1{lt}{ital x}{sub {ital F}}{lt}0.7, {ital d}{sigma}/{ital dx}{sub {ital F}} is well fit by the form (1{minus}{ital x}{sub {ital F}}){sup {ital n}} with {ital n}=3.9{plus minus}0.3. The difference between {ital n} values for {ital D}{sup {minus}} and {ital D}{sup +} is 1.1{plus minus}0.7. However, we find an asymmetry of 0.18{plus minus}0.06 favoring the production of {ital D}{sup {minus}} compared to {ital D}{sup +}. In the lower {ital P}{sub {ital T}} range, {lt}2 GeV, {ital d}{sigma}/{ital dP}{sub {ital T}}{sup 2} is well fit by the form exp({minus}{ital b}{times}{ital P}{sub {ital T}}{sup 2}) with {ital b}=1.03{plus minus}0.06 GeV{sup {minus}2}, while in the higher {ital P}{sub {ital T}} range, 0.8 to 3.6 GeV, it is well fit by the form exp({minus}{ital b}{prime}{times}{ital P}{sub {ital T}}) with {ital b}{prime}=2.76{plus minus}0.08 GeV{sup {minus}1}. The shape of the differential cross section has no significant dependence on atomic mass of the target material.