Thesis

Heavy Flavour Jets Production in Pb+Pb Collisions with the ATLAS Detector

• Call:

  IDPASC Portugal - PHD Programme 2015

• Academic Year:

  2015 / 2016

• Domain:

  Experimental Particle Physics

• Supervisor:

  Helena Santos

• Co-Supervisor:

  José Guilherme Milhano

• Institution:

  Instituto Superior Técnico

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  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, and it is expected to set in the core of the neutron stars. 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 understanding of the effects of the QGP on heavy flavour jets (collimated sprays of particles originating on the hadronization of ``bottom'' quarks). The main motivation arises because the ``bottom'' quark constitutes an excellent probe to study the nature of the energy loss suffered by the quarks while travessing the QGP. The ongoing upgrade of the ATLAS detector towards Run II (expected to re-start in April, 2015) enhances the capabilities of studying such observable. This is an experimental PhD program and the work will be developed mostly at LIP - Laboratório de Instrumentação e Física Experimental de Partículas. The student will participate in data acquisition at CERN, either of p+p collisions at 13 TeV or Pb+Pb collisions at 5.13 TeV, and will analyse the data. This analysis involves the measurement of the transverse momentum spectra of both heavy flavour jets 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++. 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 technical activities related to detector operations.