Abstract
The goal of ultrarelativistic 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. Modifications of the spectral functions 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 proceedings, dilepton results from RHIC are reviewed and the status as well as prospects of low-mass dilepton measurements at the LHC are given.
Highlights
I. e. pairs of oppositely charged leptons (e+e− or μ+μ−), have proven to be a useful tool to study the properties of the strongly coupled medium created in ultrarelativistic heavy-ion collisions at the Super Proton Synchrotron (SPS), the Relativistic Heavy Ion Collider (RHIC), and most recently the Large Hadron Collider (LHC)
Most dileptons result from hadron decays long after the fireball has ceased to exist
With its short lifetime the ρ spectral function should be very sensitive to the predicted restoration of chiral symmetry inside the fireball
Summary
I. e. pairs of oppositely charged leptons (e+e− or μ+μ−), have proven to be a useful tool to study the properties of the strongly coupled medium created in ultrarelativistic heavy-ion collisions at the Super Proton Synchrotron (SPS), the Relativistic Heavy Ion Collider (RHIC), and most recently the Large Hadron Collider (LHC). With its short lifetime the ρ spectral function should be very sensitive to the predicted restoration of chiral symmetry inside the fireball. Enhancements of the invariant-mass spectrum of dileptons above the “cocktail” of ordinary hadron decays had been observed in heavy-ion collisions by the CERES and NA60 experiments at the SPS [1, 2]. The latter was able to precisely determine that the enhancement was consistent with a broadening of the ρ spectral function, but could not be described by a “dropping” mass scenario as originally predicted by Brown and Rho [3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
