Model investigations of the correlation between the mean transverse momentum and anisotropic flow in shape-engineered events

TL;DR

This study investigates how the correlation between mean transverse momentum and flow in heavy-ion collisions depends on initial conditions, system size, shape, and viscosity, using simulations from AMPT and EPOS models.

Contribution

It demonstrates that the $ ho(v^{2}_{2},[p_{T}])$ correlator is sensitive to initial geometry but not significantly affected by medium viscosity, aiding model discrimination.

Findings

$ ho(v^{2}_{2},[p_{T}])$ correlator agrees qualitatively across models.

Correlator sensitive to initial geometry, insensitive to $ ext{η/s}$ variations.

Potential for constraining initial-state models and medium properties.

Abstract

The correlation between the event mean-transverse momentum $[p_{\mathrm{T}}]$, and the anisotropic flow magnitude $v_n$, $\rho(v^{2}_{n},[p_{T}])$, has been argued to be sensitive to the initial conditions in heavy-ion collisions. We use simulated events generated with the AMPT and EPOS models for Au+Au at $\sqrt{\textit{s}_{NN}}$ = 200 GeV, to investigate the model dependence and the response and sensitivity of the $\rho(v^{2}_{2},[p_{T}])$ correlator to collision-system size and shape, and the viscosity of the matter produced in the collisions. We find good qualitative agreement between the correlators for the string melting version of the AMPT model and the EPOS model. The model investigations for shape-engineered events as well as events with different viscosity ($\eta/s$), indicate that $\rho(v^{2}_{2},[p_{T}])$ is sensitive to the initial-state geometry of the collision system but is insensitive to sizable changes in $\eta/s$ for the medium produced in the collisions. These findings suggest that precise differential measurements of $\rho(v^{2}_{2},[p_{T}])$ as a function of system size, shape, and beam-energy could provide more stringent constraints to discern between initial-state models and hence, more reliable extractions of $\eta/s$.