Flow Fluctuations from Early-Time Correlations in Nuclear Collisions

TL;DR

This paper links flow fluctuations in nuclear collisions to initial state inhomogeneities, showing how early-stage correlations influence observed flow and momentum fluctuations through a comprehensive hydrodynamic framework.

Contribution

It introduces a unified framework connecting initial state fluctuations to flow and momentum fluctuations, including quantitative predictions for flow fluctuations and their relation to the ridge.

Findings

Flow fluctuations originate from initial state inhomogeneities.

Longitudinal correlations from early Glasma stage explain fluctuation data.

Computed elliptic and triangular flow fluctuations and their connection to the ridge.

Abstract

We propose that flow fluctuations have the same origin as transverse momentum fluctuations. The common source of these fluctuations is the spatially inhomogeneous initial state that drives hydrodynamic flow. Longitudinal correlations from an early Glasma stage followed by hydrodynamic flow quantitatively account for many features of multiplicity and $p_t$ fluctuation data. We develop a framework for studying flow and its fluctuations in this picture. We then compute elliptic and triangular flow fluctuations, and study their connections to the ridge.