Speaker
Description
We study the contribution to the polarization of $\Lambda$ hyperons in relativistic nuclear collisions at high energy from the decays of $\Sigma^*(1385)$ and $\Sigma^0$, which are the predominant sources of $\Lambda$ production besides the primary component, as a function of the $\Lambda$ momentum. Particularly, we determine the longitudinal component of the mean spin vector as a function of the azimuthal angle and show that it has a very similar pattern to the primary one, if primary $\Sigma^*$ and $\Sigma^0$ polarization follow the predictions of local thermodynamic equilibrium in a relativistic fluid. Therefore, we conclude that the secondary decays cannot account for the discrepancy between experimental data and hydrodynamic model predictions of the longitudinal polarization of $\Lambda$ hyperons recently measured by the STAR experiment at RHIC.
