# Quark Matter 2018

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

## Measurement of the underlying event in the presence of high pileup at ATLAS

May 15, 2018, 5:00 PM
2h 40m
First floor and third floor (Palazzo del Casinò)

### First floor and third floor

#### Palazzo del Casinò

Poster Collectivity in small systems

### Speaker

Alexander Milov (Weizmann Institute of Science (IL))

### Description

In meaurements of bulk charged-particle production, the kinematic characteristics of produced hadrons and correlation between them in the presence of the hard scattering signatures is a very interesting topic for understanding the physics processes relevant in small collision systems. Extensive data samples have been accumulated by the LHC experiments experiments to conduct these studies in $pp$ collisions. These measurements, however, are complicated by the presence of many pileup vertices in each bunch crossing which contaminate direct studies of the characteristics of the underlying event. This problem is addressed in the ATLAS detector using an event mixing technique which allows to correct for the presence of the pileup on a statistical basis. The implementation, result and limitations of the techniques are presented in this poster. The results use $\sqrt{s} = 8$ and 13 TeV data samples with a combined integrated luminosity exceeding 50 fb$^{-1}$.

Collaboration ATLAS Presenter name already specified Experiment

### Primary authors

Barbara Krystyna Wosiek (Institute of Nuclear Physics Polish Academy of Sciences (PL)) Alexander Milov (Weizmann Institute of Science (IL))