Universe Colloquium: Low-mass dileptons: A thermometer for the hottest stuff in the universe

by Torsten Dahms (TUM)

Wednesday 13 Nov 2013, 16:30 → 17:30 Europe/Berlin

seminar room, basement (Excellence Cluster Universe)

The goal of ultra-relativistic heavy-ion collisions at RHIC and the LHC is to study the properties of the quark-gluon plasma (QGP), a phase of matter with partonic degrees of freedom. Electromagnetic radiation, in form of photons or lepton pairs, is a penetrating probe that allows the investigation of the full time evolution and dynamics of the produced matter, as it does not undergo strong interaction in the final state. The dilepton spectrum is extremely rich in physics sources: Thermal black-body radiation is of particular interest as it carries information about the QGP temperature. Modification of the spectral function of light vector mesons are linked to the potential restoration of chiral symmetry in the QGP phase. Correlated lepton pairs from semi-leptonic charm and beauty decays provide additional information about the heavy-quark energy loss. Finally, the suppression of quarkonia in the QGP give access to an independent temperature measurement. In this talk, dilepton results from RHIC will be reviewed and an outlook for possible low-mass dilepton measurements at the LHC will be given. The Universe Colloquium is followed by a social gathering with wine and cheese.