Can Schwarzschild Black Holes Be Accelerators of Spinning Massive Particles?

TL;DR

This paper investigates whether Schwarzschild black holes can accelerate spinning massive particles to high energies, revealing that particle spin can significantly increase collision energies near non-rotating black holes.

Contribution

It extends previous studies by analyzing the effects of particle spin on collision energies around non-rotating black holes using Hanson-Regge-Hojman theory.

Findings

Spinning particles can achieve higher collision energies near Schwarzschild black holes.

Analysis of trajectories shows increased invariant energy due to particle spin.

Causality constraints limit the maximum achievable energies.

Abstract

It is known that the center-of-mass energy of the collision of two massive particles following geodesics around a black hole presents a maximum. The maximum energy increases when the black hole is endowed with spin, and for a maximally rotating hole this energy blows up, offering, in principle, a unique probe of fundamental physics. This work extends the latter studies by considering that the colliding particles possess intrinsic angular momentum (spin), described by the Hanson-Regge-Hojman theory of spinning particles. By analyzing planar trajectories of spinning particles around non-rotating black holes, a significant increase of the invariant collision energy is found. Radial turning points, causality constraints, and limitations of the theory are discussed.