Dresden 2013 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 40: Schwerionenkollisionen und QCD Phasen

HK 40.4: Vortrag

Dienstag, 5. März 2013, 17:45–18:00, HSZ-204

Prospects of Low-Mass Dielectron Measurements in ALICE with an upgraded Central Barrel Detector — •Patrick Reichelt — Institut für Kernphysik, Goethe-Universität Frankfurt

The measurement of electron-positron pairs in the low invariant mass region allows to study the vacuum and in-medium properties of light vector mesons. Dielectrons also probe the production of thermal photons in heavy-ion collisions. ALICE is well-suited to perform this measurement due to its excellent tracking and particle identification capabilities at very low momenta. However, Dalitz decays and photon conversions lead to a high combinatorial background. Additionally, coincident semi-leptonic decays of charm and anti-charm hadrons produce a continuum signal, which dominates over a thermal dielectron signal. Both contributions can be reduced by an improved Inner Tracking System, to be installed during LHC’s long shutdown 2 (2018). It will further improve the tracking efficiency at low p_T and provide excellent detection capabilities for electrons from secondary vertices like conversions and heavy-quark decays. Additionally, an upgrade of the TPC readout will substantially increase the data taking rate. The expected impact on the low-mass dielectron measurement in Pb-Pb collisions at full LHC energy will be presented.