Vorticity in isobar collisions of ₄₄⁹⁶Ru+₄₄⁹⁶Ru and ₄₀⁹⁶Zr+₄₀⁹⁶Zr at vs_NN=200 GeV

The kinematic vorticity and thermal vorticity are calculated in isobar collisions of 200 GeV Ru-96(44) + Ru-96(44) and Zr-96(40) + Zr-96(40) with different deformation parameters within the framework of Ultra-relativistic Quantum Molecular Dynamics model (UrQMD), and a little difference of vorticity between Ru-96(44) + Ru-96(44) and Zr-96(40) + Zr-96(40) collisions is observed. From the ratios of (Zr-Ru)/Ru of vorticity in different deformation cases, it is found that ratios in deformation cases decrease with the increasing of centrality (i.e. more peripheral) but increase in the case without deformation. And an opposite signal is observed for ratios between nuclear collisions with deformation and without deformation. In addition, the effect of deformation parameter beta(2) is discussed and it is found that the larger beta(2 )the deformation of the nuclei has, the higher vorticity the collision system presents in the Zr-96(40) + Zr-96(40) collisions. However, it is insensitive in the Ru-96(44) + Ru-96(44) collisions.