Darmstadt 2016 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 45: Postersession
HK 45.46: Poster
Mittwoch, 16. März 2016, 18:30–20:30, S1/05 22-24
Electron Identification and Hadron Contamination Studies in Proton-Proton Collisions with ALICE — •Anisa Dashi for the ALICE collaboration — Technische Universität München
The continuum of electron-positron pairs, produced in heavy-ion collisions, provides an excellent probe of the quark-gluon plasma and a possible chiral symmetry restoration, since these particles do not undergo strong final state interactions and hence carry information about the in-medium properties of hadrons to the detectors. To extract possible signatures, it is important to work with an electron sample of high purity, i.e. not contaminated by other particles. Dielectrons are also studied in proton-proton collisions to provide a crucial reference for the measurement in heavy-ion collisions.
This poster presents an analysis performed on a data set of pp collisions at √s = 7 TeV measured with the ALICE detector at the Large Hadron Collider. The aim of this work is to optimize the electron identification and to reduce the hadron contamination. For that, three different combinations of particle identification (PID) criteria are compared regarding the statistical significance S/σS of their dielectron signals and their electron purities. The analysis shows that one can achieve good electron identification efficiencies and high electron purities by combining the specific energy loss signals measured in the Inner Tracking System and the Time Projection Chamber with the information of the Time of Flight detector. With such a PID selection one obtains a dielectron signal with a purity higher than 82% reaching up to 96%, depending on the invariant mass.