Speaker
Description
We present a framework for spin dynamics in the quark-gluon plasma produced in relativistic heavy-ion collisions.
Under the approximation of small polarization, macroscopic spin degrees of freedom decouple from the background, and their evolution equations and transport coefficients have been computed using quantum kinetic theory as an effective microscopic foundation. The resulting hydrodynamic theory comprises 11 equations: six for the components of the spin potential, which relaxes toward thermal vorticity through nonlocal collisions exchanging orbital and spin angular momentum, and five for the spin-shear tensor, which encodes dissipative effects.
Employing this theory, we numerically solve dissipative relativistic spin hydrodynamics. We explore three interaction scenarios between constituent particles and apply the framework to compute both global and local spin polarization of $\Lambda$ hyperons in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV. Our results show that the initially vanishing spin potential relaxes toward thermal vorticity, driving global polarization. Furthermore, we demonstrate that the sign of longitudinal polarization is sensitive to the interaction type, highlighting the importance of a consistent treatment of dissipative effects in spin hydrodynamics for describing experimental data.
