This thesis offers an excellent, comprehensive introduction to the physics of the quark–gluon plasma. It clearly explains the connection between theory and experiment, making the topic accessible to non-specialists in this field. The experimental work, which contributes significantly to our understanding of the quark–gluon plasma, is described in great detail. The results described in the final chapters of the thesis provide interesting new ideas about the connection between proton-proton and Pb-Pb collisions. Simone Schuchmann received the 'ALICE Thesis Award 2016' for this excellent work.

Measurements of the production of muons from heavy-flavour hadron decays in Pb-Pb collisions at √sNN = 5.02 and 2.76 TeV using the ALICE detector at the LHC are reported. The nuclear modification factor RAA at √sNN = 5.02 TeV is measured at forward rapidity (2.5 y

Charged-particle spectra at midrapidity are measured in Pb-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair √sNN = 5.02 TeV and presented in centrality classes ranging from most central (0-5%) to most peripheral (95-100%) collisions. Possible medium effects are quantified using the nuclear modification factor (RAA) by comparing the measured spectra with those from proton-proton collisions, scaled by the number of independent nucleon-nucleon collisions obtained from a Glauber model. At large transverse momenta (8

Transverse-momentum (pT) differential yields of electrons from semileptonic heavy-flavour hadron decays have been measured in the most central (0-10%) and in semi-central (20-40%) Pb-Pb collisions at sNN---√=2.76 TeV. The corresponding production cross section in pp collisions has been measured at the same energy with substantially reduced systematic uncertainties with respect to previously published results. The modification of the yield in Pb-Pb collisions with respect to the expectation from an incoherent superposition of nucleon-nucleon collisions is quantified at mid-rapidity (|y|

This thesis presents the first measurement of charmed D0 meson production relative to the reaction plane in Pb–Pb collisions at the center-of-mass energy per nucleon-nucleon collision of √sNN = 2.76 TeV. It also showcases the measurement of the D0 production in p–Pb collisions at √sNN = 5.02 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement of the D0 azimuthal anisotropy with respect to the reaction plane indicates that low- momentum charm quarks participate in the collective expansion of the high-density, strongly interacting medium formed in ultra-relativistic heavy-ion collisions, despite their large mass. This behavior can be explained by charm hadronization via recombination with light quarks from the medium and collisional energy loss. The measurement of the D0 production in p–Pb collisions is crucial to separate the effect induced by cold nuclear matter from the final- state effects induced by the hot medium formed in Pb–Pb collisions. The D0 production in p–Pb collisions is consistent with the binary collision scaling of the production in pp collisions, demonstrating that the modification of the momentum distribution observed in Pb–Pb collisions with respect to pp is predominantly induced by final-state effects such as the charm energy loss.