Collectivity in ultra-peripheral heavy-ion collisions

TL;DR

This paper uses advanced 3D dynamical simulations to explore collective phenomena in ultra-peripheral heavy-ion collisions at the LHC, focusing on the elliptic flow hierarchy and the role of longitudinal flow decorrelations.

Contribution

It introduces a comprehensive simulation framework combining 3DGlauber, MUSIC, and UrQMD to study collectivity in ultra-peripheral collisions, extrapolating from asymmetric p+Pb data.

Findings

Elliptic flow hierarchy is influenced by longitudinal flow decorrelations.

The framework quantitatively models collectivity in small asymmetric systems.

Simulations suggest strong final-state effects in ultra-peripheral collisions.

Abstract

We present full (3+1)D dynamical simulations to study collective behavior in ultra-peripheral nucleus-nucleus collisions (UPC) at the Large Hadron Collider (LHC) with the 3DGlauber+MUSIC+UrQMD framework. By extrapolating from asymmetric p+Pb collisions, we simulate a quasi-real photon $\gamma^*$ interacting with the Pb nucleus in an ultra-peripheral collision at the LHC, assuming strong final-state effects. We study the elliptic flow hierarchy between p+Pb and $\gamma^*$+Pb collisions, which is dominated by the difference in longitudinal flow decorrelations. Our theoretical framework provides a quantitative tool to study collectivity in small asymmetric collision systems at current and future collider experiments.