Total forward and differential cross sections of neutral D mesons produced in 500 GeV/c #pi#~--nucleon interactions

摘要

We measure the neutral D total forward cross section and the differential cross sections as functions of Feynman-x(x_F) and transverse momentum squared for 500 GeV / c #pi#~- -nucleon interactions. The results are obtained from 88 990 +- 460 reconstructed neutral D mesons from Fermilab experiment E791 using the decay channels D~0 -> K~- #pi#~+ and D~0 -> K~- #pi#~+ #pi#~- #pi#~+ (and charge conjugates). We extract fit parameters from the differential cross sections and provide the first direct measurement of the turnover point in the x_F distribution, 0.0131 +- 0.0038. We measure an absolute D~0 + D-bar~0 (x_F > 0) cross section of 15.4_(-2.3)~(+1.8) #mu#barn / nucleon (assuming a linear A dependence). The differential and total forward cross sections are compared to theoretical predictions and to results of previous experiments.