Massless spinning test particles in vacuum algebraically special spacetimes

TL;DR

This paper explores the behavior of massless spinning particles in special vacuum spacetimes using advanced mathematical formalisms, providing explicit solutions and insights into their motion.

Contribution

It extends the Mathisson-Papapetrou model to massless particles and explicitly integrates equations of motion along principal null directions in algebraically special vacuum spacetimes.

Findings

Explicit solutions for particle motion in specific spacetimes

Insights into the influence of spacetime algebraic properties on particle dynamics

Demonstration of the model's applicability to known vacuum solutions

Abstract

The motion of massless spinning test particles is investigated using the Newman-Penrose formalism within the Mathisson-Papapetrou model extended to massless particles by Mashhoon and supplemented by the Pirani condition. When the "multipole reduction world line" lies along a principal null direction of an algebraically special vacuum spacetime, the equations of motion can be explicitly integrated. Examples are given for some familiar spacetimes of this type in the interest of shedding some light on the consequences of this model.