# XII Workshop on Particle Correlations and Femtoscopy

Jun 12 – 16, 2017
Other Institutes
Europe/Zurich timezone

## Global polarization of Lambda hyperons in Au+Au Collisions at RHIC BES

Jun 14, 2017, 9:00 AM
25m
Other Institutes

#### Other Institutes

Nikhef Science Park 105 1098XG Amsterdam The Netherlands

### Speaker

Isaac Upsal (Ohio State University)

### Description

Non-central heavy-ion collisions have large ($\sim 10^{3} \hbar$) angular momentum which may be transferred, in part, to the quark-gluon plasma through shear forces that generate a vortical substructure in the hydrodynamic flow field. The vortical nature of the system is expected to polarize emitted hadrons along the direction of system angular momentum. $\Lambda$ and $\overline{\Lambda}$ hyperons, which reveal their polarization through their decay topology, should be polarized similarly.

These same collisions are also characterized by dynamic magnetic fields with magnitudes as large as $10^{14}$ Tesla. A splitting between $\Lambda$ and $\overline{\Lambda}$ polarization may signal a magnetic coupling and provide a quantitative estimate of the field strength at freeze out.

This presentation will cover the first observation of a global hyperon polarization in non-central Au+Au collisions at Beam Energy Scan energies as well as the dependence of this signal on $\Lambda$ kinematic variables ($\phi$, $y$, and $p_T$).

List of tracks Chiral magnetic effect and wave, chiral vortical effect

### Primary author

Isaac Upsal (Ohio State University)

### Presentation materials

 LisaWPCF2017polarization.pdf LisaWPCF2017polarization.pptx