Diffractive production of charm from flavor-excitation diagrams

A perturbative quantum-chromodynamics (QCD) analysis of heavy-quark production in hadron collisions can account for the observed diffractive ${\Lambda }_c^{+}$ production. The dominant graphs are flavor excitation by gluons ($q\overline{c}\to q\overline{c}$ and $g\overline{c}\to g\overline{c}$) of charm. The essential input is a hard charm $x$ distribution. Estimates are made for the ${\Lambda }_b^0$ cross section.