# 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!

## Event Plane Dependence of Di-hadron Correlations with Event Shape Engineering at the STAR Experiment

15 May 2018, 16:40
20m
Sala Perla, 1st Floor (Palazzo del Casinò)

### Sala Perla, 1st Floor

#### Palazzo del Casinò

Parallel Talk Correlations and fluctuations

### Speaker

Ryo Aoyama (University of Tsukuba)

### Description

In relativistic high energy collisions, hard scattered partons can fragment into two back-to-back jets. These jets can be used as hard probes to study properties of the Quark Gluon Plasma created in nucleus-nucleus collisions. Di-hadron correlations with respect to high $p_T$ trigger particles are a useful tool to study the interactions between jets and the medium in high-energy heavy-ion collisions. The jet-medium interplay depends on the in-medium path length of initial partons and the system evolution.

Centrality dependence of the jet-like recoil peak magnitude opposite the trigger particle in di-hadron correlations has been widely interpreted as a signature of path-length dependence of jet modification. However, the path length differs between in-plane (the same direction as the event plane, the shorter axis of elliptic shape) and out-of-plane (the perpendicular direction to the event plane) trigger particles because of the almond-like shape of two overlapping nuclei. Therefore, one can exert a measure of control over the recoil jet's in-medium path length by selecting the trigger particle's azimuthal direction with respect to the event plane. Event shape engineering (ESE) has been proposed as a powerful tool to control the initial geometrical shape. ESE constrains the event-by-event flow fluctuations by selecting the magnitude of the flow vector $q_n$. A more detailed study for jet-medium interplay will be possible with ESE than previous event plane dependent di-hadron correlations at the STAR experiment. Here, we present di-hadron correlations in Au+Au collisions at $\sqrt{s_{NN}}=$200 GeV as a function of both the trigger azimuthal angle with respect to the event plane and various ESE selections. The result of this analysis will provide new insights on the geometry and path-length dependence of jet-medium interactions as well as the effect of collective medium expansion on jet modification.

Content type Experiment STAR Presenter name already specified

### Primary author

Zhenyu Ye (University of Illinois at Chicago)