Alternative ansatz to wounded nucleon and binary collision scaling in high-energy nuclear collisions

TL;DR

The paper presents TRENTO, a new model for initial conditions in high-energy nuclear collisions that accurately describes multiplicity distributions and eccentricity harmonics, aligning with experimental data across various collision systems.

Contribution

Introduction of TRENTO, a parametric initial condition model that improves upon existing models by accurately describing multiplicity and flow data without binary collision terms.

Findings

TRENTO reproduces multiplicity distributions in pp, pA, and AA collisions.

The model generates eccentricity harmonics consistent with flow measurements.

TRENTO is compatible with ultra-central uranium-uranium collision data.

Abstract

We introduce TRENTO, a new parametric initial condition model for high-energy nuclear collisions based on eikonal entropy deposition via a "reduced thickness" function. The model simultaneously describes experimental proton-proton, proton-nucleus, and nucleus-nucleus multiplicity distributions, and generates nucleus-nucleus eccentricity harmonics consistent with experimental flow constraints. In addition, the model is compatible with ultra-central uranium-uranium data unlike existing models that include binary collision terms.