Semiholography for heavy ion collisions

TL;DR

This paper introduces semiholography as a framework to integrate perturbative and nonperturbative QCD effects in heavy ion collisions, aiming to better understand quark-gluon plasma formation and collective flow.

Contribution

It develops a semiholographic approach to incorporate nonperturbative effects into existing theories for heavy ion collisions, enabling more comprehensive modeling.

Findings

Feasibility of numerical computations demonstrated

Framework can confront experimental data with few parameters

Proposes a new non-Newtonian fluid description of collective flow

Abstract

The formation of QGP in heavy ion collisions gives us a great opportunity for learning about nonperturbative dynamics of QCD. Semiholography provides a new consistent framework to combine perturbative and non-perturbative effects in a coherent way and can be applied to obtain an effective description for heavy ion collisions. In particular, it allows us to include nonperturbative effects in existing glasma effective theory and QCD kinetic theory for the weakly coupled saturated degrees of freedom liberated by the collisions in the initial stages in a consistent manner. We argue why the full framework should be able to confront experiments with only a few phenomenological parameters and present feasibility tests for the necessary numerical computations. Furthermore, we discuss that semiholography leads to a new description of collective flow in the form of a generalised non-Newtonian fluid. We discuss some open questions which we hope to answer in the near future.