Probing of EoS with clusters and hypernuclei

TL;DR

This paper investigates how different nuclear equations-of-state affect heavy-ion collision observables, using a microscopic transport model to compare with experimental data, and finds that a soft momentum-dependent EoS best reproduces the data.

Contribution

It introduces the use of the PHQMD transport approach to study the impact of various EoS on cluster and hypernuclei formation and collective flow in heavy-ion collisions.

Findings

Soft momentum-dependent EoS best matches experimental data.

Hard EoS show similar qualitative trends to soft EoS.

Cluster and hypernuclei observables are sensitive to the EoS choice.

Abstract

The study of the nuclear equation-of-state (EoS) is a one of the primary goals of experimental and theoretical heavy-ion physics. The comparison of recent high statistics data from the STAR Collaboration with transport models provides a unique possibility to address this topic in a yet unexplored energy domain. Employing the microscopic N-body Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) transport approach, which allows to describe the propagation and interactions of hadronic and partonic degrees of freedom including cluster and hyper-nucleus formation and dynamics, we investigate the influence of different EoS on bulk observables, the multiplicity, $p_T$ and rapidity distributions of protons, $\Lambda$s and clusters up to A=4 as well as their influence on the collective flow. We explore three different EoS: two static EoS, dubbed 'soft' and 'hard', which differ in the compressibility modulus, as well as a soft momentum dependent EoS. We find that a soft momentum dependent EoS reproduces most baryon and cluster observables, including the flow observables, quantitatively, however, hard EOS show a similar trend.