Jets Production in Pb+Pb Collisions with the ATLAS Detector
IDPASC Portugal - PHD Programme 2016
2016 / 2017
Experimental Particle Physics
José Guilherme Milhano
Instituto Superior Técnico
Laboratório de Instrumentação e Física Experimental de Partículas
Quantum Chromodynamics --- the theory of the strong interactions --- predicts that at large temperatures, hadronic matter (bound states of quarks and gluons) becomes deconfined. This plasma of quarks and gluons, which is known to behave as a nearly perfect liquid, was the prevailing state of the Universe shortly after the Big Bang. Nucleus-nucleus collisions at the Large Hadron Collider (LHC) provide an unique opportunity to recreate the Quark Gluon Plasma (QGP) in the laboratory energy frontier. The capabilities of ATLAS, namely large acceptance and high granularity calorimeters, afford excellent handles for QGP studies. A major goal of the Heavy Ion Program of the LHC is the understanding of the effects of the QGP on jets, namely the study of the nature of the energy loss suffered by the quarks and gluons while travessing the QGP. The bottom quark, in particular, constitutes an excellent probe. Due to its large virtuality, Q, it has a formation time,$\Delta t$ $\approx$1/Q $\approx$ 0.1 fm/c, much smaller than the formation time of the QGP at the LHC ($\approx$10 fm/c). This is an experimental PhD program which includes a strong phenomenological component. 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 and will analyse the data. The analysis will explore strategies to separate b-quarks jets originating directly from the hard process from those arising from gluon splitting with the aim of devising novel experimental observables sensitive to the different energy loss of quarks and gluons. For such studies he(she) will need to develop algorithms in C++. Furthemore, she/he will concurrently 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.