Open heavy flavour production in small systems with ALICE

Abstract

Charm and beauty production measurements in proton–proton (pp) collisions are an important test of perturbative QCD calculations, based on the factorisation approach, which assumes universal fragmentation functions among different collision systems. Recent measurements of charm baryon production at midrapidity in small systems show a baryon-to-meson ratio significanlty higher than that in e+e− and e−p collisions: this observation suggests that charm fragmentation is not universal across different collision systems. Therefore, measurements of charm baryon production are fundamental to characterise the charm quark hadronisation in pp and proton–lead (p–Pb) collisions at the LHC energies. In these proceedings, the latest measurements of D0, D+ and Ds+ mesons, the new measurements of Λc+, Ξc0,+, Σc0,++, the first measurement of Ωc0 baryons and of the non-prompt Λc+, performed with the ALICE detector at midrapidity in pp collisions at s=5.02 and s=13TeV are presented. Furthermore, the recent Λc+/D0 yield ratio, measured down to pT=0 in pp and p–Pb collisions will be discussed together with the measurements of the charm fragmentation fractions into hadrons in pp and p–Pb collisions at sNN=5.02TeV. This rich set of experimental results challenges existing theoretical calculations.