Accelerating hydrodynamic description of pseudorapidity density and the initial energy density in p+p, Cu+Cu, Au+Au, and Pb+Pb collisions at RHIC and LHC

TL;DR

This paper uses advanced hydrodynamic models with acceleration to analyze pseudorapidity distributions in various high-energy collision systems, enabling more accurate estimates of initial energy densities beyond traditional models.

Contribution

It introduces accelerating solutions of relativistic hydrodynamics to better describe experimental data and extract initial energy densities in diverse collision systems at RHIC and LHC.

Findings

Accurately describes pseudorapidity distributions across multiple collision systems.

Provides improved estimates of initial energy density over traditional models.

Demonstrates the importance of acceleration in hydrodynamic modeling.

Abstract

A known class of analytic, exact, accelerating solutions of prefect relativistic hydrodynamics with longitudinal acceleration is utilized to describe results on the pseudorapidity distributions for different collision systems. These results include $dN/d\eta$ measured in p+p, Cu+Cu, Au+Au, and Pb+Pb collisions at RHIC and LHC, in a broad centrality range. Going beyond the traditional Bjorken model, from the accelerating hydrodynamic description we determine the initial energy density and other thermodynamic quantities in those collisions.