# Particle dynamics and geometric optics in Chern-Simons black holes

## TL;DR

This paper investigates how the Chern-Simons coupling constant influences various physical properties of black holes, including mass, particle collision energy, energy extraction efficiency, and polarization rotation, revealing some properties are independent of the coupling.

## Contribution

It provides a detailed analysis of the effects of Chern-Simons coupling on black hole physics, highlighting which properties depend on or are independent of this coupling.

## Key findings

- Hawking mass for slowly rotating black holes is independent of the coupling constant.
- Energy gain and efficiency in the Penrose process are unaffected by the coupling.
- Polarization vector rotation depends on the Chern-Simons coupling constant.

## Abstract

In this paper we study the effects of the coupling constant of the Chern-Simons modified gravity on some physical properties of black holes. The Hawking mass is one of the proposed definitions of quasilocal mass. We find that, for slowly rotating Chern-Simons black holes, the Hawking mass is independent of the coupling constant. Next, we show the dependence on the centre of mass energy, for two neutral colliding particles, of coupling constant and the rotation parameter. We also investigate energy extraction through Penrose process and find that the energy gain and efficiency of the Penrose process are independent of this coupling constant. Rotation of the polarization vector is also studied for dependence on the Chern-Simons coupling constant.