Formalism of hydrodynamics with spin degrees of freedom

TL;DR

This paper reviews a hydrodynamics framework that incorporates spin degrees of freedom, enabling the description of spin polarization evolution in massive particles within relativistic fluid dynamics.

Contribution

It introduces a formalism based on the GLW tensors that generalizes standard hydrodynamics to include spin, with applications demonstrated using the Bjorken model.

Findings

Framework allows calculation of spin polarization observables.

Demonstrates applicability to relativistic heavy-ion collision scenarios.

Provides a method to connect hydrodynamics with experimental polarization data.

Abstract

In this article we review the perfect-fluid hydrodynamics with spin framework proposed recently. This framework generalises the standard relativistic hydrodynamics framework to include spin degrees of freedom and provides a natural method to describe the spin polarization evolution of massive spin 1/2 particles. This formalism is based on the GLW (de Groot - van Leeuwen - van Weert) energy-momentum tensor and spin tensor. We show here using Bjorken model that how this spin hydrodynamics framework may be used for the determination of the observables which describes the particle polarization measured in the experiment.