Initial conditions from the shadowed Glauber model

TL;DR

This paper enhances the two-component Monte-Carlo Glauber model for Uranium+Uranium collisions by incorporating nucleon shadowing, successfully resolving discrepancies with experimental data and aligning initial condition fluctuations with gluon saturation physics.

Contribution

The paper introduces nucleon shadowing into the Glauber model, improving agreement with experimental observations and initial fluctuation predictions.

Findings

Addresses the absence of predicted features in data

Nucleon shadowing suppresses initial fluctuation variations

Aligns initial condition fluctuations with gluon saturation models

Abstract

The two component Monte-Carlo Glauber model predicts a knee-like structure in the centrality dependence of elliptic flow $v_2$ in Uranium+Uranium collisions at $\sqrt{s_{NN}}=193$ GeV. It also produces a strong anti-correlation between $v_2$ and $dN_{ch}/dy$ in the case of top ZDC events. However, none of these features have been observed in data. We address these discrepancies by including the effect of nucleon shadowing to the two component Monte-Carlo Glauber model. Apart from addressing successfully the above issues, we find that the nucleon shadow suppresses the event by event fluctuation of various quantities, e.g. $\varepsilon_2$ which is in accordance with expectation from the dynamical models of initial condition based on gluon saturation physics.