On sensitivity of nucleus deformation on final-state flow harmonics

TL;DR

This study investigates how nuclear deformation influences collective flow in relativistic heavy-ion collisions, revealing sensitivities of flow harmonics to deformation parameters and confirming their utility as probes of initial geometry.

Contribution

The paper introduces a detailed analysis of the impact of nuclear deformation parameters on flow harmonics using a hybrid hydrodynamic model, expanding understanding of initial geometry effects.

Findings

Flow harmonics are sensitive to deformation parameters, especially in Au+Au collisions.

U+U collisions show less sensitivity of flow harmonics to geometrical parameters.

Results support flow harmonics as effective probes of initial geometry fluctuations.

Abstract

In this work, we explore the effect of deformation of the nuclei on collective flow in relativistic heavy-ion collisions. The parameter associated with the geometrical deformation in the Glauber model is tuned to reproduce the empirical multiplicity probability distributions correctly. Subsequently, the particle spectra and collective flows for Au+Au and U+U collisions are evaluated using a hybrid hydrodynamic code CHESS. We analyze the effects of the degrees of freedom associated with the IC on the final-state flow harmonics by exploring the parameter space of the former. The connection between the deformation parameters, specifically $\beta_2$ and $\beta_4$, and the flow anisotropies is scrutinized. In particular, deviations in elliptic flow at $p_{\mathrm{T}}\sim 2$ GeV are observed at smaller values of $\beta_2$ in Au+Au collisions. On the other hand, for U+U collisions, the averaged overall flow harmonics are found to be less sensitive to the geometrical parameters. Despite the difference in the model's specifications, our findings largely confirm those obtained in the literature employing different approaches, which indicate that flow harmonics can be used as a sensible probe for the initial geometry fluctuations and to discriminate between different theoretical models.