# Quark Matter 2018

13-19 May 2018
Venice, Italy
Europe/Zurich timezone
The organisers warmly thank all participants for such a lively QM2018! See you in China in 2019!

## Dielectron production in pp collisions at sqrt(s)= 7 TeV with ALICE

15 May 2018, 17:00
2h 40m
First floor and third floor (Palazzo del Casinò)

### First floor and third floor

#### Palazzo del Casinò

Poster Electromagnetic and weak probes

### Speaker

Horst Sebastian Scheid (Johann-Wolfgang-Goethe Univ. (DE))

### Description

Dileptons are a prime probe of the deconfined state of strongly-interacting matter, the Quark-Gluon Plasma (QGP), produced in high-energy heavy-ion collisions, as they are not affected by final-state interactions and produced at all stages of the collision. A measurement of the thermal radiation from the QGP in the dielectron intermediate-mass region gives information on the medium temperature. In this region the main component of the dielectron continuum is coming from correlated semi-leptonic decays of charm and beauty hadrons, which may be affected by the energy loss and collectivity of charm and beauty quarks in the QGP. Therefore, it is crucial to understand the primordial heavy-flavour production in vacuum and find a way to separate this contribution from the thermal signal of the QGP. This can be studied in proton-proton collisions.

In this poster, the measurement of correlated e$^+$e$^-$. pairs in pp collisions at $\sqrt{s}$ = 7 TeV with ALICE will be presented. In particular, we will show how the measured distance of closest approach (DCA) of the electrons to the primary vertex of the collision gives the possibility to separate prompt and non-prompt dielectron pairs. The results will be compared with the expectations from known hadronic sources as a function of $m_{\rm ee}$, $p_{\rm T,ee}$ and $DCA_{\rm ee}$. The extraction of the charm and beauty cross sections from a fit of the data with different Monte-Carlo generators will be discussed, as well as the measured fraction of direct photons to inclusive photons.

Centralised submission by Collaboration Presenter name already specified Experiment ALICE

### Primary author

Horst Sebastian Scheid (Johann-Wolfgang-Goethe Univ. (DE))