Feasibility study of the reconstruction of D*(2010)+ mesons at low transverse momentum with ALICE detector at LHC

Abstract

Quantum Chromodynamics predicts that under condition of extreme temperature and/or pressure the ordinary matter undergoes a phase transition to the so called Quark-GluonPlasma (QGP) [2]. Contrary to ordinary matter, in QGP the quarks and gluons are deconfined and therefore free to move. In addition QGP is believed to have been the state of matter in our early Universe, a few microseconds after the Big Bang. In order to study its properties, QGP is reproduced in laboratory via heavy ion collisions. Due to the short lifetime (∼ 10−15 s) and the small size (∼ 10−15 m) of the plasma produced, the only possibility of studying its properties is by using probes. One of the most effective probes is the charm quark. The idea is to measure the modification of the production of particles containing a charm quark in a system where QGP is produced, like lead-lead (Pb-Pb) collisions at the Large Hadron Collider (LHC) [4], with respect a system where QGP is not formed, like proton-proton (p-p) collisions. Any modification can then be attributed to the charm quark energy loss in the hot and dense QCD matter, driven by key properties of the plasma like density and/or viscosity. In this thesis, we study the possibility of reconstructing the D∗ particle, a charmed meson, in p-p collisions at low transverse momentum. Besides constituting the necessary baseline for Pb-Pb studies, the measurement of the production of D mesons is a key observable to test perturbative QCD calculations.