First talk (30'):
Heavy flavours are recognised as excellent probes of the colour-deconfined state of the hadronic matter called quark-gluon plasma (QGP) created in heavy-ion collisions. Due to the very short time scale characterising their production, they experience the whole evolution of the system serving as Brownian-motion markers of the QGP. Measurements of open heavy-flavour hadron production in heavy-ion collisions give insight in the mechanisms of heavy-quark transport and energy loss in the hot and dense QCD matter, and the abundances of different hadron species are fundamental to investigate the hadronisation processes.
Measurements of the production of heavy-flavour hadrons in proton-proton collisions provide the baseline for observations of hot-medium effects in heavy-ion collisions, as well as tests of perturbative QCD calculations. In recent years, they gained additional interest due to the observation of unexpected features typical of the heavy-ion phenomenology.
In this seminar, the most recent results of the ALICE collaboration on the production of Λc, Ξc, and Σc baryons in pp collisions, D mesons from beauty-hadron decays in pp and Pb-Pb collisions, the charm production cross section in pp and p-Pb collisions from low-mass dielectron measurements, and the azimuthal anisotropy in the production of open charm and beauty hadrons in Pb-Pb collision are presented.
Second talk (30'):
Jets and high transverse momentum (pT) hadrons are excellent probes of the QGP produced in heavy-ion (HI) collisions because the partons inside jets interact with the medium, leading to jet energy loss and substructure modification - a phenomenon called jet quenching. New measurements that probe several aspects of jet quenching in Pb-Pb collisions with the ALICE detector will be shown in new regions of phase space for HI jet measurements at the LHC. These include measurements of jet suppression using machine learning techniques, measurements of jet acoplanarity using hadron-jet correlations, and the first unfolded groomed jet substructure measurements. This talk will discuss these new results, including comparisons to jet quenching models, and how they further our knowledge of the microscopic composition of the QGP. Additionally, measurements in pp collisions of groomed inclusive and heavy-flavour tagged jet substructure that are calculable with pQCD will be shown. Jets and high-pT hadron measurements in small systems (pp, p-Pb) help elucidate initial and final state effects and constrain nuclear PDFs. ALICE has set limits on the magnitude of jet quenching in small systems, which complement observations of flow-like signatures in these systems. This talk will also discuss new results in small systems with ALICE and how they fit into our understanding of QCD matter.
Michelangelo Mangano, Monica Pepe-Altarelli and Guillaume Unal.