Azimuthal angular correlations between D*⁺ mesons and charged hadrons in proton-proton collisions at 13 TeV with the ALICE experiment at the LHC

Collisions of heavy-ions at ultra-relativistic speeds allow for the creation of a new state of matter where quarks and gluons are deconfined in the so-called Quark-Gluon Plasma (QGP). It is believed that such a state of matter was present in our Universe a few microseconds after the Big Bang. The QGP properties are studied by means of probes. Heavy quarks (charm and beauty) are among the most suitable probes since, due to their large masses, are produced early in the collision and therefore they witness the full evolution of the system while losing energy in the QGP via collisional and radiative processes. The measurements of heavy quarks production and of their azimuthal correlation with lighter particles in small systems (proton-proton and proton-ion collisions) constitute a stringent test of perturbative Quantum Chromodynamics (pQCD) and a mandatory reference for the heavy-ion measurements in order to disentangle cold and hot nuclear matter effects. In this manuscript, we investigate the azimuthal correlations of charmed mesons (D*, D⁰, D⁺) with charged particles. The study is performed on real data and simulation for different collision energies. The proton-proton data used were collected by the ALICE Collaboration at CERN Large Hadron Collider while the simulation studies are performed with PYTHIA8 and EPOS3/EPOS[at]sHQ event generators. By means of correlation studies, we aim to shed light on the heavy-quarks production mechanisms setting constraints to pQCD calculations. At the same time, we build the necessary reference for future D mesons correlation studies in heavy-ion collisions targeted to investigate charm and beauty in medium energy loss. (author)