Speaker
Description
For the past years, different observables related to the spin polarization of hadrons such as $\Lambda$-Baryons have continued to attract attention and pose theoretical challenges.
While some measurements (such as the global polarization) can be reproduced by assuming the spins of the particles to be equilibrated, more differential observables (such as the local polarization) remain a subject of active discussion.
In order to account for the finite duration of the process of spin relaxation, i.e., the approach of the spin potential to the thermal vorticity, a theory of relativistic spin hydrodynamics can be used.
Similar to the Bloch equations that describe the (nonrelativistic) dynamics of magnetization, such a theory has to provide evolution equations for the spin potential, which remains a dynamical quantity.
I will showcase the construction of this theoretical framework over the past years. Starting from the equations of quantum field theory, an intermediate quantum-kinetic framework is developed, which subsequently produces the equations of dissipative spin hydrodynamics in the appropriate limit. Finally, the equations are solved numerically and are shown to be able to reproduce the experimental data.