Speaker
Description
Recent measurements on $\Lambda$ hyperon's polarization suggest a strong correlation with the local fluid vorticity in hydrodynamic models. Jet-medium interactions induce a generic vortex ring structure of the fluid kinematic vorticity along the quenched jet axis. In this talk, we propose a novel ring observable R^J to capture such a ring excitation in the fluid's flow field by high-energy partons [1]. This observable $\mathcal{R}^{\hat{J}}$ shows a strong sensitivity to the fluid's shear viscosity. We verify our results with event-by-event hydrodynamic backgrounds. Furthermore, we expand our (3+1)D calculations by systematically studying the $\mathcal{R}^{\hat{J}}$'s dependence on the temporal-spatial size and magnitude of the deposited energy-momentum current. Finally, we quantify how the angular distribution of $\mathcal{R}^{\hat{J}}$ is correlated with the background flow field and can serve as a tomographic probe for the flow gradient field.
[1] W. M. Serenone, J. G. P. Barbon, D. D. Chinellato, M. A. Lisa, C. Shen, J. Takahashi, and G. Torrieri, "Lambda polarization from thermalized jet energy,'' Phys. Lett. B820, 136500 (2021)
