# Relaxation Time for Strange Quark Spin in Rotating Quark-Gluon Plasma

## TL;DR

This paper investigates the mechanisms behind strange quark spin polarization in rotating quark-gluon plasma, concluding that spin remains unchanged from creation to hadronization, with vorticity fluctuations having negligible effect.

## Contribution

It introduces and analyzes two mechanisms—vorticity fluctuations and helicity flips—that could influence strange quark spin polarization, finding both are ineffective within relevant timescales.

## Key findings

- Strange quark spin remains unchanged from creation to hadronization.
- Vorticity fluctuations do not significantly affect hyperon spin.
- Both considered mechanisms lead to equilibration times too large for heavy ion collisions.

## Abstract

Experiments at the Relativistic Heavy Ion Collider (RHIC) have measured the net polarization of $\Lambda$ and $\bar{\Lambda}$ hyperons and attributed it to a coupling between their spin and the vorticity of the fluid created in heavy ion collisions. Equipartition of energy is generally assumed, but the dynamical mechanism which polarizes them has yet to be determined. We consider two such mechanisms: vorticity fluctuations and helicity flip in scatterings between strange quarks and light quarks and gluons. With reasonable parameters both mechanisms lead to equilibration times orders of magnitude too large to be relevant to heavy ion collisions. Our conclusion is that strange quark spin or helicity is unchanged from the time they are created to the time they hadronize. A corollary is that vorticity fluctuations do not affect the hyperon spin either.