Evolution of eccentricities induced by geometrical and quantum fluctuations in proton-nucleus collisions

TL;DR

This paper analytically investigates how initial geometrical and quantum fluctuations influence azimuthal eccentricities in high-energy proton-nucleus collisions, using Gaussian models and linearized Yang-Mills equations.

Contribution

It introduces an analytical framework to compute eccentricities from initial fluctuations in proton-nucleus collisions, incorporating both geometrical and quantum effects.

Findings

Analytical expressions for energy density correlators and eccentricities.

Time evolution of eccentricities approximated using linearized Yang-Mills equations.

Quantitative insights into fluctuation effects on collision geometry.

Abstract

We compute the azimuthal eccentricities arising from initial stage fluctuations in high energy proton-nucleus collisions at proper times $\tau \geq 0^+$. We consider two sources of fluctuations, namely the geometrical structure of the proton and the fluctuation of color fields carried by both proton and nucleus. Describing these effects with Gaussian models allows us to analytically calculate the one- and two-point correlators of energy density, from which the eccentricities are obtained. We compute the proper time evolution of these quantities by approximating the Glasma dynamics in terms of linearized Yang-Mills equations, which we solve by assuming free field propagation and adopting the dilute-dense limit.