Measurement of the elliptic flow of $^3$He and $^3_\Lambda$H in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.36$ TeV

TL;DR

This paper reports the first measurement of elliptic flow coefficients for light nuclei and hypernuclei in Pb-Pb collisions at 5.36 TeV, offering insights into their production mechanisms and phase-space distributions.

Contribution

It provides the first experimental elliptic flow data for (anti)${}^3_{\Lambda}$H and $^3ar{ ext{He}}$, testing hydrodynamic and coalescence models in heavy-ion collisions.

Findings

Elliptic flow of (anti)${}^3_{\Lambda}$H and $^3ar{ ext{He}}$ measured for the first time.

Results constrain models of hadronization and nuclear formation.

Data supports coalescence as a key mechanism in hypernuclei production.

Abstract

The first measurement of the elliptic flow coefficient of (anti)${}^3_{\Lambda}$H and the study of the $v_2$ of $^3\overline{\mathrm{He}}$ measured in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.36$ TeV with the ALICE detector are presented. Based on the large data sample of approximately five billion events collected in 2023 during the LHC Run 3 data taking, these measurements provide important insights into the production mechanism of (anti)(hyper)nuclei, as well as into the phase-space distributions of nucleons and hyperons produced in heavy-ion collisions. The results are discussed in the context of hydrodynamic and coalescence models, highlighting how the measurement of the elliptic flow of nuclei, such as helium and hypertriton, provides critical constraints on hadronization models.