Effects of sub-nucleonic fluctuations on the longitudinal structure of heavy-ion collisions

TL;DR

This paper investigates how sub-nucleonic fluctuations influence the longitudinal structure of heavy-ion collisions, connecting initial state models to experimental observables through advanced hydrodynamic simulations.

Contribution

It introduces a comprehensive study linking sub-nucleonic fluctuations in initial states to longitudinal decorrelation observables using a 3D initial state model and 3+1D hydrodynamics.

Findings

Sub-nucleonic fluctuations significantly affect longitudinal flow decorrelations.

Inclusion of sub-nucleonic fluctuations improves agreement with experimental data.

Different fluctuation sources alter the magnitude of longitudinal correlations.

Abstract

Sub-nuclear fluctuations in the initial state of heavy-ion collisions impact not only transverse long-range correlations of small systems, but also the creation of longitudinal structures, seen in particle detectors as longitudinal decorrelation observables. In this work, we study the emergence of long-range rapidity correlations in nuclear collisions based on the 3D resolved McDIPPER initial state model, and for the first time, connect it to experimental observables using the 3+1D viscous hydrodynamics framework CLVisc. We include different sources of fluctuations at the nucleon and subnucleon level and study the effects of these additional fluctuation sources on the longitudinal structure of relevant observables, such as the flow decorrelations and directed flow.