Elliptic and triangular flow of (anti)deuterons in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

TL;DR

This paper reports the first measurements of elliptic and triangular flow of (anti)deuterons in Pb-Pb collisions at 5.02 TeV, comparing results with hydrodynamic and coalescence models to understand particle production mechanisms.

Contribution

It provides new experimental data on (anti)deuteron flow coefficients and evaluates their agreement with various theoretical models at LHC energies.

Findings

(Anti)deuteron $v_2$ shows mass ordering at low $p_T$.

$v_2$ is between coalescence and blast-wave model predictions.

$v_3$ approximately follows mass number scaling, unlike $v_2$.

Abstract

The measurements of the (anti)deuterons elliptic flow ($v_2$) and the first measurements of triangular flow ($v_3$) in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collisions $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV are presented. A mass ordering at low transverse momentum ($p_{\rm T}$) is observed when comparing these measurements with those of other identified hadrons, as expected from relativistic hydrodynamics. The measured (anti)deuterons $v_2$ lies between the predictions from the simple coalescence and blast-wave models, which provide a good description of the data only for more peripheral and for more central collisions, respectively. The mass number scaling, which is violated for $v_2$, is approximately valid for the (anti)deuterons $v_3$. The measured $v_2$ and $v_3$ are also compared with the predictions from a coalescence approach with phase-space distributions of nucleons generated by iEBE-VISHNU with AMPT initial conditions coupled with UrQMD, and from a dynamical model based on relativistic hydrodynamics coupled to the hadronic afterburner SMASH. The model predictions are consistent with the data within the uncertainties in mid-central collisions, while a deviation is observed in central centrality intervals.