The McDIPPER: A novel saturation-based 3+1D initial state model for Heavy Ion Collisions

TL;DR

The paper introduces McDIPPER, a new 3+1D initial state model for heavy-ion collisions based on the CGC framework, capable of rapidity-resolved charge deposition and event-by-event simulations.

Contribution

It presents a novel saturation-based 3+1D initial state model that can generate rapidity-resolved conserved charges for heavy-ion collisions.

Findings

Successfully computes gluon and quark densities using IP-Sat model

Reproduces key observables like eccentricities and flow decorrelation

Framework allows systematic improvements with higher-order calculations

Abstract

We present a new 3D resolved model for the initial state of ultrarelativistic heavy-ion collisions, based on the $k_\perp$-factorized Color Glass Condensate hybrid approach. The McDIPPER 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 extended to lower energies by including sub-eikonal corrections the channels included. We present relevant observables, such as the eccentricities and flow decorrelation, as tests of this new approach.