Measurement of charm and beauty production at central rapidity versus charged-particle multiplicity in proton-proton collisions at √s = 7 TeV

Prompt D mesonand non-prompt J/$\psi$ yields are studied as a function of the multiplicityof charged particlesproduced in inelastic proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=7$ TeV. The results are reported as a ratio between yields in a given multiplicityinterval normalised to the multiplicity-integratedones (relative yields). They are shown as a function of the multiplicityof charged particlesnormalised to the average value for inelastic collisions(relative charged-particle multiplicity). D$^0$, D$^+$ and D$^{*+}$ mesonsare measured in five $p_{\rm T}$ intervals from 1 to 20 GeV/$c$ and for $|y| 1.3$ GeV/$c$ and $|y| 0$. The fraction of non-prompt J/$\psi$ in the inclusive J/$\psi$ yields shows no dependence on the charged-particle multiplicityat central rapidity. Charm and beauty hadron relative yields exhibit a similar increase with increasing charged-particle multiplicity. The measurements are compared to PYTHIA 8, EPOS 3 and percolation calculations.