Longitudinal correlations in the initial stages of ultra-relativistic nuclear collisions

I.-K Yoo,Wojciech Broniowski,Piotr Bożek

doi:10.1051/epjconf/201714105003

Abstract

In this talk we review some of our results for the longitudinal correlations in connection with recent experimental data, in particular for the {\em torque} effect and for the two-particle correlations in pseudorapidity, $C(\eta_1,\eta_2)$. The model framework involves event-by-event fluctuations of the initial conditions, followed with 3D viscous hydrodynamic evolution and statistical hadronization.

Highlights

In the long-range rapidity correlations, the phenomenon is manifest through the shape-flow transmutation depicted in Fig. 1: If the transverse sections in the initial state are similar in the forward (F) and backward (B) directions, the corresponding harmonic flow are similar, up to decorrelation effects from fluctuations
As originally proposed in Ref. [4] in the framework of the wounded-nucleon model [5], the decollimation happens as a combination of two features:
The participants must have asymmetric emission profiles in the rapidity, with a preference that a participant shines preferably in its forward direction [6]. These lead to the event-by-event torque, as shown in the right part of Fig. 2, appearing independently for subsequent Fourier components

Summary

Introduction

In the long-range rapidity correlations, the phenomenon is manifest through the shape-flow transmutation depicted in Fig. 1: If the transverse sections in the initial state are similar in the forward (F) and backward (B) directions, the corresponding harmonic flow (directions of the principal axes, magnitude) are similar, up to decorrelation effects from fluctuations. There are event-by-event fluctuations in the number of the F and B going participants (left part of Fig. 2). These lead to the event-by-event torque, as shown in the right part of Fig. 2, appearing independently for subsequent Fourier components.

Results

Conclusion