Hyperon Dynamics in Heavy-ion Collisions near threshold energy

TL;DR

This study uses a quantum molecular dynamics model to investigate hyperon production in heavy-ion collisions, focusing on isospin and in-medium effects, and finds that hyperon yields and ratios are sensitive to nuclear symmetry energy and in-medium potentials.

Contribution

It introduces a hyperon-nucleon potential from chiral effective field theory into the model and accounts for threshold energy corrections, providing new insights into hyperon dynamics.

Findings

$ ext{Sigma}$ yields are suppressed with the potential.

Hyperons are emitted in the reaction plane.

$ ext{Sigma}^{-}/ ext{Sigma}^{+}$ ratio depends on nuclear symmetry energy.

Abstract

Within the framework of quantum molecular dynamics transport model, the isospin and in-medium effects on the hyperon production in the reaction of $^{197}$Au + $^{197}$Au are investigated thoroughly. A repulsive hyperon-nucleon potential from the chiral effective field theory is implemented into the model, which is related to the hyperon momentum and baryon density. The correction on threshold energy of the elementary hyperon cross section is taken into account. It is found that the $\Sigma$ yields are suppressed in the domain of midrapidity and kinetic energy spectra with the potential. The hyperons are emitted in the reaction plane because of the strangeness exchange reaction and reabsorption process in nuclear medium. The $\Sigma^{-}/\Sigma^{+}$ ratio depends on the stiffness of nuclear symmetry energy, in particular in the high-energy region (above 500 MeV).