# 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!

## The sign change of the four-particle cumulant in small systems from hydrodynamics and momentum conservation

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

### First floor and third floor

#### Palazzo del Casinò

Poster Collectivity in small systems

### Speaker

Dr Guo-Liang Ma (Shanghai INstitute of Applied Physics (SINAP), CAS)

### Description

The azimuthal cumulants, $c_2\{2\}$ and $c_2\{4\}$, originating from the global conservation of transverse momentum [1] in the presence of hydro-like elliptic flow are calculated [2]. We observe a sign change of $c_2\{4\}$ for small number of produced particles, which is in a qualitative agreement with the recent ATLAS measurement of multi-particle azimuthal correlations with the subevent cumulant method [3]. Our results offer a new insight into the problem of the onset of collectivity in small systems.

References
1. Adam Bzdak and Guo-Liang Ma, arXiv: 1710.00653.
2. Adam Bzdak and Guo-Liang Ma, in preparation.
3. The ATLAS Collaboration, arXiv:1708.03559.

Centralised submission by Collaboration Presenter name already specified Theory

### Primary author

Dr Guo-Liang Ma (Shanghai INstitute of Applied Physics (SINAP), CAS)

### Co-author

Adam Bzdak (AGH University of Science and Technology)