Feasibility study of the detection of higher D∗ meson states with ALICE at LHC

Abstract

Shortly after the big bang happened, a phase of matter called the quark gluon plasma (QGP) was created. This is a plasma where the constituents of nucleons roam freely instead of being bound tightly into particles. The QGP is researched at the Large Hadron Collider at CERN in an experiment called ALICE (A Large Ion Collider Experiment) where at high energies, protons and heavy ions are collided. Mesons made up of heavy quarks such as the charm and bottom quark can be used to probe the QGP. Heavy quarks are produced in the early stages of heavy ion collisions and thus journey through the QGP’s full evolution. In previous years, the J/ψ (c¯ c) and Υ (b¯ b) mesons have been used as a temperature probe. In this thesis we proposed the possibility to use higher D∗ meson states, in order to investigate the maximum QGP temperature. Therefore the feasibility of the detection of D∗(2010)+, D∗ 0(2400)0, D1(2420)0 and D∗ 2(2460)0 was investigated. Simulations of 10 million pp collisions were executed at a center of mass energy of 13 TeV using ROOT and PYTHIA. The results showed that, depending on the species, we can expect a range of a few millions to a few billions of D mesons produced within ALICE detector acceptance |η| < 0.9. Such numbers give a reasonably safe number of D mesons in order to perform the reconstruction in LHC run III data sample. Furthermore, evidence was provided that we cannot aim, in data, to reconstruct the higher D∗ meson states below a pT of 1-2 GeV/c due to intrinsic limits on the ALICE low pT tracking.