Production mechanisms of open-heavy flavor mesons

In this paper we discuss different mechanisms of open-heavy flavor meson production. Using the color dipole framework, we analyze in detail the contributions of the conventional two-pomeron fusion and the three-pomeron fusion correction. In a parameter-free way we found that the three-pomeron mechanism is significant for $D$-meson production in the small-$p_{T}$ kinematics, although it is less important at large $p_{T}$, as well as for $B$-mesons. The inclusion of the three-pomeron mechanism significantly improves the agreement of theoretical predictions with experimental data in the small-$p_{T}$ kinematics. We also consider the non-prompt charmonia production, and demonstrate that the theoretical results are in reasonable agreement with experimental data. Finally, we compare the theoretical predictions for the dependence on multiplicity of co-produced hadrons to experimental data recently measured by the ALICE collaboration. We found that, contrary to naive expectations, the contribution of the three-pomeron mechanism has only a mild effect on the self-normalized observables in the range of multiplicities studied at ALICE, and for this reason the two-pomeron fusion mechanism can describe reasonably well the experimentally observed multiplicity dependence.