# Boost invariant formulation of the chiral kinetic theory

## TL;DR

This paper develops a boost-invariant chiral kinetic equation, revealing new effects like the side-jump contribution to transverse current and a unique pattern called chiral circular displacement, enhancing understanding of chiral particle dynamics.

## Contribution

It introduces a boost-invariant formulation of the chiral kinetic theory, incorporating expansion effects and interpreting particle number conservation in this context.

## Key findings

- Identification of two expansion-related terms in the chiral kinetic equation
- Discovery of the chiral circular displacement pattern in transverse current
- Clarification of physical interpretation of particle number conservation

## Abstract

We formulate the chiral kinetic equation with the longitudinal boost invariance. We particularly focus on the physical interpretation of the particle number conservation. There appear two terms associated with the expansion, which did not exist in the non-chiral kinetic equation. One is a contribution to the transverse current arising from the side-jump effect, and the other is a change in the density whose flow makes the longitudinal current. We point out a characteristic pattern in the transverse current driven by the expansion, which we call the chiral circular displacement.