# Quark Matter 2019 - the XXVIIIth International Conference on Ultra-relativistic Nucleus-Nucleus Collisions

3-9 November 2019
Wanda Reign Wuhan Hotel
Asia/Shanghai timezone

## Low-mass dielectron measurements in minimum-bias pp collisions at 5.02 TeV with ALICE

4 Nov 2019, 17:40
20m
Wanda Han Show Theatre & Wanda Reign Wuhan Hotel

#### Wanda Han Show Theatre & Wanda Reign Wuhan Hotel

Poster Presentation Electromagnetic probes

### Speaker

Leonhardt Heinrich Viebach (Johann-Wolfgang-Goethe Univ. (DE))

### Description

Low-mass dielectrons play a key role in the understanding of the chiral-symmetry restoration and in the study of the Quark-Gluon Plasma (QGP) created in relativistic heavy-ion collisions. In the intermediate-mass region, the measurement of thermal dielectrons from the QGP is nevertheless very challenging at the LHC due to the dominant contribution of e$^{+}$e$^{-}$ pairs from open-charm and -beauty hadron decays. To single out the interesting signal characteristics of the QGP, the primordial e$^{+}$e$^{-}$ pair production in vacuum needs to be first understood. It can be studied in minimum-bias proton-proton collisions. Dielectron measurements in elementary collision systems serve not only as a reference for the heavy-ion analysis but provide also a test for Monte-Carlo event generators, aiming to reproduce the heavy-flavour production mechanisms.

In this poster, we will present the status of the dielectron analysis in pp collisions at $\sqrt{s}$ = 5.02 TeV with ALICE. The dielectron yield is studied as a function of invariant mass, pair transverse momentum, and pair transverse impact parameter (DCA$_{\rm ee}$). The latter helps to disentangle prompt and non-prompt dielectron sources. The results can be compared to the expectated dielectron cross section from known hadronic sources.

### Primary author

Leonhardt Heinrich Viebach (Johann-Wolfgang-Goethe Univ. (DE))