29 January 2024 to 2 February 2024
CERN
Europe/Zurich timezone

Topological separation of dielectron signals using machine learning in Pb--Pb collisions with ALICE

31 Jan 2024, 16:00
5m
61/1-201 - Pas perdus - Not a meeting room - (CERN)

61/1-201 - Pas perdus - Not a meeting room -

CERN

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Poster 2 ML for analysis : event classification, statistical analysis and inference, including anomaly detection Poster Session

Speaker

Jerome Jung (Goethe University Frankfurt (DE))

Description

Dielectrons are an exceptional tool to study the evolution of the medium created in heavy-ion collisions. In central collisions, the energy densities are sufficient to create a quark-gluon plasma (QGP). At LHC energies, the dominant background process for the measurements of thermal e$^{+}$e$^{-}$ pairs originating from the QGP are correlated HF hadron decays which dominate the dielectron yield for invariant masses above 1.1 GeV/$c^2$. Their contribution is modified in the medium compared to elementary collisions to an unknown extent, leading to large uncertainties in the subtraction of known hadronic sources.

Alternatively, a topological separation can be utilised to disentangle them from the contribution of thermal dielectrons originating from the primary vertex.
As machine learning (ML) algorithms have achieved state-of-the-art performance in a variety of high-energy physics analyses, deep neural networks (DNNs) can be applied to capture the complex multidimensional correlations in the tracking parameters to identify these pairs.

In this poster, a DNN to classify dielectron sources based on their decay topology with the ALICE detector will be presented for simulated Pb--Pb collisions at $\sqrt{s_{\text{NN}}}=5.02$ TeV. Their performance will be compared to the established analysis on the distance-of-closes approach (DCA) to the primary vertex.
Finally, the way these ML techniques could be incorporated in future dielectron analysis will be discussed.

Author

Jerome Jung (Goethe University Frankfurt (DE))

Presentation materials