D- and B-meson relative yield as a function of the relative charged-particle multiplicity at central rapidity calculated with the PYTHIA 8.157 event generator The different c and b quark production processes are separated on the top panels: first hard process, hard process in multiple interactions (MPI), gluon splitting from hard processes and initial/final state radiation (ISR/FSR). The bottom panels present the multiplicity dependence in several $\pt$ intervals for prompt D-meson production, on the left for all contributions and on the right for first hard process only The coloured lines represent the calculation distributions, whereas the shaded bands represent their statistical uncertainties at given values of $({\rm d}N_{\rm ch}/{\rm d}\eta) \big/ \langle {\rm d}N_{\rm ch}/{\rm d}\eta \rangle$ The diagonal (dashed) line is drawn to guide the eye