Heavy-flavour production in proton–proton collisions with the ALICE experiment

László Gyulai

doi:10.1088/1742-6596/1690/1/012165

Abstract

The production of heavy-flavour hadrons in high-energy hadronic collisions is a unique source of information on various aspects of quantum chromodynamics (QCD). Production of heavy-flavour hadrons in proton-proton collisions allows the test of perturbative QCD models, while the comparison of mesons and baryons with heavy-flavour quarks can differentiate between fragmentation scenarios. Multiplicity-dependent measurements allow for the understanding of semi-hard vacuum QCD effects, as well as to study the coalescence mechanisms of heavy-flavour quarks with light and strange quarks. Recent results from the ALICE experiment in proton-proton collisions on the production of D mesons and leptons from the decay of heavy-flavour hadrons, as well as charmed baryons, are presented in this contribution. Furthermore, the multiplicity dependence of self-normalised heavy-flavour electron yields, as well as that of strange to non-strange D-meson and charmed baryon-to-meson ratios are also shown.

Highlights

Heavy-flavour quarks are produced in the initial stage of heavy-ion collisions via partonic hard scatterings
In proton–proton collisions, heavy-flavour particles can be primarily used for testing calculations based on perturbative quantum chromodynamics, study flavourdependent fragmentation, and to set a baseline for nuclear modification in heavy-ion collisions
Collectivity was observed prior to that in heavy-ion collisions, where it is attributed to the presence of the strongly-interacting quark–gluon plasma (QGP) [2]

Summary

Introduction

Heavy-flavour quarks (charm and beauty) are produced in the initial stage of heavy-ion collisions via partonic hard scatterings. They can be used to study the initial hard processes and the properties of the hot and cold nuclear medium present in high-energy heavy-ion collisions. Collectivity was observed prior to that in heavy-ion collisions, where it is attributed to the presence of the strongly-interacting quark–gluon plasma (QGP) [2] It is unlikely, that the QGP is produced in a substantial volume in pp collisions, due to insufficient energy density. The ALICE experiment [4] provides a great opportunity for studying heavy-flavour hadrons due to its high-precision tracking system. In case of the investigation of semi-leptonic decay channels, electrons from charm and beauty quarks are reconstructed in the central barrel, and their contributions are statistically separated on the basis of the impact parameter distribution of decay electrons, while muons from charm and beauty quarks are reconstructed in the forward muon spectrometer

Production of heavy-flavour hadrons in pp collisions

Fragmentation of heavy-flavour quarks: mesons and baryons

Conclusions