Heavy-flavour production and multiplicity dependence in pp and p--Pb collisions with ALICE

TL;DR

This paper reports on ALICE measurements of heavy-flavour (D-mesons and electrons) production in proton-proton and proton-lead collisions, exploring multiplicity dependence, cold nuclear matter effects, and charm participation in collective phenomena at LHC energies.

Contribution

It provides new experimental data on heavy-flavour production and correlations in small collision systems, enhancing understanding of QCD processes and cold nuclear matter effects.

Findings

D-meson yields increase with multiplicity in pp and p--Pb collisions.

Cold nuclear matter effects influence charm production in p--Pb collisions.

Charm quarks participate in collective motion in small systems.

Abstract

The production of heavy quarks in pp collisions provides a precision test of perturbative QCD calculations at the LHC energies. More complex collision systems like p--Pb collisions allow studies of cold nuclear matter effects, such as modifications of the parton distribution functions at small x and of the $\kt$ broadening effect. We present the ALICE results of prompt D-meson production as a function of the charged-particle multiplicity, in pp and p--Pb collisions at $\sqrt{s}=7$ TeV and $\sqrt{s_{NN}}=5.02$ TeV respectively. The per-event yield of D mesons in different multiplicity and $\pt$ intervals are compared for pp and p--Pb collisions to study the contribution of multi-parton interactions to open-charm production. Angular correlations of prompt D mesons and heavy-flavour decay electrons with charged hadrons in pp and p-Pb collisions are also shown in different kinematic ranges and compared to pQCD models. These measurements provide information on the charm fragmentation processes, on cold nuclear matter effects on charm production, and on the participation of charm in the collective motion arising in small collision systems like p-Pb.