Figure 5

$\pt$-differential production cross section of prompt $\Dplus$ mesonswith $|y|< 0.5$ in the interval \mbox{$1< \pt< 24 \gev/c$}, in pp collisions at$\sqrt s =7 \tev$ The cross section is compared to three pQCD calculations:FONLL  (top-left panel), GM-VFNS (top-right panel) and a leading order (LO) calculation based on$k_{\rm T}$-factorisation  (bottom panel) The ratios of the data to the three calculated cross sections are shownin the lower part of each panel. In the data-to-theory ratios the 3.5\%normalisation uncertainty due to the luminosity determination is not includedin the systematic uncertainty on the data points.