  Due to the large masses of the charm and bottom quarks, their production
cross sections are calculable within the perturbative QCD. This makes the
heavy-quark mesons important observables in high-energy collisions of protons
and nuclei. However, the available calculations for heavy-flavored-meson
hadroproduction have been somewhat problematic in reliably describing the cross
sections across the full kinematic range from zero to very high $p_{\rm T}$.
This has put some question marks on the robustness of LHC heavy-flavored-meson
measurements in studying the partonic structure of the colliding hadrons and
nuclei. Here, we introduce SACOT-$m_{\rm T}$ - a novel scheme for open
heavy-flavour hadroproduction within the general-mass variable-flavour-number
formalism that solves this problem. The introduced scheme is an analogue of the
SACOT-$\chi$ scheme often used for deeply-inelastic scattering in global
analyses of PDFs.
