# 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!

## Importance of initial and final state effects for azimuthal correlations in p+Pb collisions

May 15, 2018, 3:00 PM
20m
Sala Mosaici-1, 3rd Floor (Palazzo del Casinò)

### Sala Mosaici-1, 3rd Floor

#### Palazzo del Casinò

Parallel Talk Collectivity in small systems

### Speaker

Moritz Greif (University of Frankfurt)

### Description

We investigate the relative importance of initial and final state effects on azimuthal correlations in low and high multiplicity p+Pb collisions at LHC energies. By matching the classical Yang-Mills dynamics of pre-equilibrium gluon fields (IP-GLASMA) to a perturbative QCD based parton cascade for the final state evolution (BAMPS) on an event-by-event basis, we find that signatures of both the initial state correlations and final state interactions are seen in azimuthal correlation observables, such as $v_2\{2P C\}(p_T)$, with their relative strength depending on the event multiplicity and transverse momentum. Initial state correlations dominate elliptic flow in low multiplicity events for transverse momenta $p_T > 2~\mathrm{GeV}$. While final state interactions are dominant in high multiplicity events and at low momenta, we find that initial state correlations strongly affect $v_2\{2P C\}(p_T)$ for $p_T>2$ GeV as well as the pT integrated $v_2\{2P C\}$. By carrying out a systematic multiplicity scan, we can also probe the dynamics on the border of initial state dominated to final state dominated - but not yet fully developed hydrodynamic – regime. We predict at which multiplicity and transverse momentum many-body QCD effects in the initial state can be experimentally unveiled.

Content type Theory Presenter name already specified

### Primary authors

Moritz Greif (University of Frankfurt) Soeren Schlichting (University of Washington) Bjoern Schenke (Brookhaven National Lab) Carsten Greiner (University of Frankfurt)

### Presentation materials

 NO_VIDEO_PDF_QM2018_Moritz_Greif_Initial_and_Final_State.pdf QM2018_Moritz_Greif_Initial_and_Final_State.pptx