München 2019 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 20: Heavy-Ion Collisions and QCD Phases IV

HK 20.4: Vortrag

Dienstag, 19. März 2019, 14:45–15:00, HS 12

Application of MVA techniques to the J/ψ measurement via the di-electron decay channel with ALICE at the LHC — •Alena Harlenderova for the ALICE collaboration — GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt

The J/ψ meson is an important probe of the Quark-Gluon Plasma due to the color screening of the quark-antiquark potential in the hot deconfined medium. At LHC energies, a strong reduction of J/ψ suppression in comparison to lower RHIC energies has been observed in Pb-Pb collisions, consistent with additional J/ψ production via (re)generation mechanisms. A precise measurement of J/ψ in pp collisions serves as a baseline for studies in Pb-Pb collisions.

At mid-rapidity, ALICE has the unique capability to reconstruct J/ψ down to zero p_T at the LHC. However, this measurement via the di-electron decay channel suffers from a small signal-to-background ratio, in particular in Pb-Pb collisions. The use of MultiVariate Analysis (MVA) techniques can help us to suppress the background while keeping the signal largely unaffected. The resulting larger signal significance leads to an improvement of the precision of the J/ψ measurement. In this talk, the application of MVA techniques to the J/ψ analysis via the di-electron decay channel will be presented.