Elliptic and triangular flow anisotropy in deuteron-gold collisions at RHIC and proton-lead collisions at the LHC

TL;DR

This study demonstrates that elliptic and triangular flow patterns observed in small collision systems like deuteron-gold and proton-lead can be explained by relativistic hydrodynamics with fluctuating initial conditions, aligning well with experimental data.

Contribution

It provides the first detailed hydrodynamic modeling of flow anisotropies in small systems at RHIC and LHC energies, highlighting the role of initial state fluctuations.

Findings

Elliptic and triangular flow are sizable in both systems.

Flow results agree with experimental measurements.

Elliptic flow is smaller in proton-lead than in deuteron-gold collisions.

Abstract

We study elliptic and triangular flow in the collisions of deuteron-gold nuclei at $\sqrt{s_{\rm NN}} = 200$ GeV at RHIC and of proton-lead nuclei at $\sqrt{s_{\rm NN}} = 5.02$ TeV at the LHC, utilizing (3+1)-dimensional ideal hydrodynamics for the dynamic evolution of the fireball and a Glauber-based Monte-Carlo energy deposition model for simulating the fluctuating initial conditions. Sizable values of elliptic and triangular flow are obtained for both colliding systems, and the results are consistent with PHENIX, ALICE, ATLAS and CMS measurements. For these studied centralities, we find that the elliptic flow in proton-lead collisions is smaller than deuteron-gold collisions, while the triangular flows are comparable in both colliding systems. Our results indicate that the observed collective anisotropic flow in deuteron-gold and proton-lead collisions may be obtained from relativistic hydrodynamic evolution of the fireball with initial state fluctuations.