Heavy Flavour Jets Production in Pb+Pb Collisions with the ATLAS Detector
IDPASC Portugal - PHD Programme 2017
2017 / 2018
Experimental Particle Physics
Faculdade de Ciências - Universidade de Lisboa
Laboratório de Instrumentação e Física Experimental de Partículas
Quantum Chromodynamics, the theory of the strong interactions, predicts that matter should exhibit two distinct phases - a hadronic phase at lower temperatures, where the degrees of freedom are composite bound states of quarks and gluons, and a partonic phase at extreme conditions of energy densities or temperatures. The latter corresponds to a deconfined system and it is thought to be equivalent to a plasma of quarks and gluons. Such a deconfined system would have occurred a few microseconds after the Big Bang. Nucleus-nucleus collisions at the Large Hadron Collider (LHC) provide an excellent opportunity to create the Quark Gluon Plasma (QGP) in the laboratory energy frontier. The ATLAS experiment provides essential capabilities to study it, namely large acceptance, high granularity calorimeters, tracking detectors and muon spectrometers. A major goal of the Heavy Ion Program of the LHC is the study of heavy flavour jets (collimated sprays of particles originating on the hadronization of ``bottom'' quarks). The motivation arises because the ``bottom'' quark constitutes an excellent probe to infer the properties of the QGP through the study of the nature of its energy loss suffered while traversing the medium. The student will participate in data acquisition at CERN, either of p+p collisions at 13 TeV or Pb+Pb collisions at 5 TeV, and will analyse the data. This analysis involves the measurement of the transverse momentum spectra of both heavy flavour jets (``bottom'' and ``charm'') and the ones that result from the hadronization of ``up'', ``down'' and ``strange'' quarks. For such measurements he(she) will need to develop algorithms in C++. This study is a very relevant contribution to the success of the ATLAS heavy ion program. The student will present his(her) work in the regular international meetings of the ATLAS. Furthemore, he(she) will participate in the technical activities in which the ATLAS/LIP group is involved, namely in the Tile calorimeter and/or in Trigger system. The student should have solid computing skills, namely in C++ programming, and must be available to travel to CERN for short periods (1, 2 weeks), several times in the year, in order to participate in the data acquisition and in the analysis group meetings, as well as in technical activities related to detector operations.