Charm production and in-medium QCD energy loss in nucleus-nucleus collisions with ALICE. A performance study

Abstract

This work is aimed at studying the performance of the ALICE detector for measuring charm production in heavy ion collisions at the LHC and for investigating the properties of the deconfined quark-gluon medium formed in central nucleus-nucleus reactions by a comparison of its `opacities' to massive (charm) quarks and massless partons. The topics discussed in the thesis can be summarized as follows. Definition of a baseline for heavy quarks production cross sections and kinematical distributions at LHC energies, using (and comparing) pQCD tools (HVQMNR program) and the PYTHIA event generator. Study of the experimental issues related to the identification of the displaced decay vertices of charm mesons: track impact parameter resolution and primary vertex reconstruction. Definition of a strategy for the exclusive reconstruction of D^0 \to K\pi decays with ALICE in Pb-Pb and pp collisions and evaluation of the performance in terms of momentum range, precision and accuracy of the measurement. Study and simulation of the predicted parton energy loss effect, including a realistic description of the collision geometry and an algorithm to take into account the expected lower loss for heavy quarks (dead cone effect). Assessment of a strategy to carry out comparative measurements of the quenching of charm quarks and massless partons and evaluation of the attainable sensitivity.