Bochum 2018 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 31: Heavy Ion Collisions and QCD Phases V

HK 31.1: Gruppenbericht

Mittwoch, 28. Februar 2018, 14:00–14:30, HZO 60

Low-mass dielectron measurements in pp, p-Pb and Pb-Pb collisions with ALICE at the LHC — •Raphaelle Bailhache for the ALICE collaboration — Institut für Kernphysik, Frankfurt, Deutschland

Low-mass dielectron measurements play a key role in the study of the Quark-Gluon Plasma (QGP) created in relativistic heavy-ion collisions. At low mass, the dielectron yield is sensitive to the properties of vector mesons in the dense medium and effects due to the chiral symmetry restoration. In the intermediate mass range, dielectrons originate mainly from semielectronic decays of correlated charm and beauty hadrons, which carry information on the energy loss and thermalisation of heavy quarks in the QGP. Finally, thermal radiations from the medium contribute to the dielectron yields in a broad mass range and provide information on the temperature of the medium. To be able to study the QGP signal characteristics, pp collisions are used as vacuum reference, whereas p-Pb collisions allow the study of the cold-matter effects. Moreover, observations of collective effects in high-multiplicity pp and p-Pb collisions show surprising similarities with those in heavy-ion collisions. In this talk, we will present an overview of the dielectron measurements with ALICE at the LHC in pp, p-Pb and Pb-Pb collisions. Its implications for the production of heavy quarks and virtual photons, will be discussed, as well as possible modifications of the dielectron yield in high-multiplicity pp collisions and in Pb-Pb collisions. Finally, we will report on the analysis of pp data taken with a low-magnetic field configuration of ALICE for Run-3.