Effects of subnucleonic fluctuations on the longitudinal dynamics of heavy-ion collisions

¹ Fakultät für Physik, Universität Bielefeld, D-33615 Bielefeld, Germany
² Instituto Galego de Física de Altas Enerxías IGFAE, Universidade de Santiago de Compostela, E-15782 Galicia, Spain
³ Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University, Wuhan, 430079, China

^* e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 17 April 2026

Abstract

It is well understood that subnuclear fluctuations in the initial state of heavy-ion collisions have an important impact on the creation of long-range correlations in the transverse plane. This is also true for the creation of particle correlations along the beam direction, which can be measured in particle detectors, e.g. through longitudinal decorrelation observables. In this work, we study the emergence of long-range rapidity structures in Pb+Pb collisions using a hybrid model connecting the 3D resolved McDipper initial state model to a (3+1)D viscous hydrodynamics framework CLVisc. We include different sources of fluctuations at the (sub-)nucleon level and present the effects of their inclusion on the longitudinal structure of relevant observables, focusing in this proceedings paper on charged hadron multiplicities, baryon stopping, directed flow and flow decorrelation. We find remarkable agreement to the experimental data regarding directed flow and the rapidity resolved charge particle multiplicity.