McDIPPER: A novel saturation-based 3+1D initial-state model for heavy ion collisions

Abstract

We present a new three-dimensional resolved model for the initial state of ultrarelativistic heavy-ion collisions, based on the k⊥-factorized color glass condensate (CGC) hybrid approach. The framework responds to the need for a rapidity-resolved initial-state Monte Carlo event generator which can deposit the relevant conserved charges (energy, charge, and baryon densities) both in the midrapidity and forward (backward) regions of the collision. This event-by-event generator computes the gluon and (anti-) quark phase-space densities using the IP-Sat model, from where the relevant conserved charges can be computed directly. In the present work we have included the leading-order contributions to the light flavor parton densities. As a feature, the model can be systematically improved in the future by adding next-to-leading-order calculations (in the CGC hybrid framework) and extending to lower energies by including subeikonal corrections to the channels included. We present relevant observables, such as the eccentricities and flow decorrelation, as tests of this new approach. Published by the American Physical Society 2024