We study the kinematic and thermal vorticities in low-energy heavy-ion collisions by using the ultrarelativistic quantum molecular dynamics model. We explore their time evolution and spatial distribution. We find that the initial vorticities have a nonmonotonic dependence on the collision energy $\sqrt{s_{\mathrm{NN}}}$: as $\sqrt{s_{\mathrm{NN}}}$ grows the vorticities first increase steeply and then decrease with a turning point around $\sqrt{s_{\mathrm{NN}}}\approx 3–5$ GeV depending on the centrality.

• Received 25 February 2020
• Accepted 12 June 2020

DOI:https://doi.org/10.1103/PhysRevC.101.064908